In an adult, reciprocal relationship, both partners' needs and wants for the relationship are respected and taken into consideration, irrespective of any children either of them have.  What too often happens in a step family is that the step parent's needs and wants are disregarded, played down and marginalised, which is what has happened here.  You could have handled things a different way, yes, by prioritising your own needs more from the start, but being the sort of person your ex girlfriend was, this probably would have meant that the relationship ended sooner!  

She allowed and encouraged her 7 yr old to be irritating and spoiled, and then didn't like it when you pointed it out to her. She ignored you when you very reasonably asked her to try and work together to change things.  I think you can conclude that you are better off out of this relationship which was very one-sided,  and would never have changed, in all likelihood. 

It doesnt sound like your relationship was solid. If she moved on so quickly,  either she is a woman who needs to be with a man at all times or she had already decided the relationship was over and the argument about her daughter was the reason to end it. 

She sounds flaky. Count your blessings and move on. You'll find the right one. 

Well, she got pregnant with one man's baby while the baby she had with another man was still in diapers. Be glad you didn't become the third baby daddy, which is what she's after. She probably has to act fast to secure another 20 years of financial security before her uterus rots out.

For future reference (not with this woman hopefully)

1. kids needs

2. adults needs

3. adult wants

4. kid wants

Obviously sometmes the last two will be the other way around, but on the whole, this is how it should be.

Some examples: just because the kids want to go to the zoo one weekend doesn't mean they should get to go if that means the adults sacrificing a date night. Now if the kids were going to the zoo as part of a school trip then maybe the adults would sacrifice their date night or find another way to pay for the educational experience as education is a need for kids. If it was little Sally's birthday and all she had talked about all year was going to the zoo then the adults might choose together to sacrifice date night and take Sally to the zoo for her birthday as a special treat. That time the child's want came first, but it was discussed and agreed apon and an exception, not the norm. This is how a healthy family works. When kids ALWAYS come first there is no room for their parents to have a life of thier own or fulfilling relationships outside of parenthood. 

Of course people who claim that their kids ALWAYS come first are fooling themselves (and/or others) most of the time. Of course they make decisions that sometimes and put themselves before their kids. Everyone does. Your ex clearly wasn't minimizing the risk of passing corronavirus onto her kids when she hooked up with a new dude during a pandemic. That is not putting her kids first, it is selfishly satisfying her desires and her kids' health is a secondary consideration. What parents really mean when they say that is that they want to be seen as the perfect parent and either they don't want to say no directly so they use the kids as an excuse or they simply don't want to compromise their life for thier partner.

Another point: If you and a partner cannot find ways to communicate about difficult topics without splitting up all the time then the relationship is not going to work. Being able to communicate calmly about sensitive things is key to a healthy relationship. It isn't possible 100% of the time and of course everyone has arguments but the more we can practice the skills of good communication the better a relationship will be. 

If I were you I might spend some time looking into communication in relationships and how to improve your own communication skills while you are currently single so that you are better set up for any new relationships and can better recognise poor communicators in the future. Great communication skills enables good relationships to thrive. 

The best thing parents/adults can do for a child is model a healthy and loving relationship. Far too often parents put "the kids first" but it really only leads to entitlement and self absorbtion. In turn, parents can be in denial about their own kids. 

Find someone, if they have kids, who are REALISTIC about their children. They should also not make "the world revolve around them." If they do - run. Sounds like you are making the right choice!! Kudos to you. 

I'm sorry what are you confused about with this woman? She's got two baby daddies, be glad you aren't number three. She moved on three days after you two broke up, three days...that's just enough time to wash the sheets so your scent is gone for the new guy...uh gross!

You did the right thing. You were just another guy in her "tribe" of guys, and she has already replaced you with another guy. She did you a favor if she is that child-centric. 

You dodged a bullet here - be grateful.

meat, was never serious about you in the first place...

i will say that as hard and upset you are right now, have piece of mind that you didn’t end up wasting a decade with her, having her screw you for money or even get pregnant so you’d be her free paycheck for life

You dodged a pretty big bullet.

Advice:

1. she was probably ready to move on before you broke up. Process the grief and find someone that you can start a family with that doesnt sacrifice their relationship for the kids. Kids are number 1 responsibility but not #1 priority if in a relationship.

2. Best not to put hands on other people's kids.

3. Best not to tell someone you dont like their kids. You can be less blunt and say something like "you know, I think she hit her wall, she must be tired?" to indicate child is being irritable and irritating. Or perhaps try the local favorite "why dont you do something with kiddo, I made plans to xyz" to get away from kiddo asap. Telling a parent you dont like their kid is baaaaaad for relationships trust me. MY DH, even with all the awful, vile, evil horrible things that Feral Forger did to me and many others, is still defensive if I say anything negative about her. "you dont like my child!" Stirs something viseral in them.

You are not wrong in requiring that your XSO put you and the relationship above all else including kids. Regardless of kid biology.  Kids are the top relationship Responsibility but not the top priority.  The partners and their relationship are the unequivocal priority.

Many with flawed character will not move on until they have their next victim set up to protect their fragile or absent self worth.

Don't beat  yourself up about your X's immediate hook up with a new BF.  My XW was one of these. She would find her next victim and start cheating with them before her husband of the moment booted her ass.   As her first DH I am the only one of a long line of her marital victims who can say I don't know how the other's Johnson's taste.  The one favor she did for me was not sleeping with me while she was sleeping with her final cheat partner.   I am also the only one of her list of DH's who did not pollute his gene pool with that cavern crotched adulterous skank whore.

You have moved on, don't give her space in your head or to cause you regrets.  The failure of this relationship is on her. Not you.

The most valuable lesson for you is... she is obviously not the love of your life.  Don't over think it, just realize this unequivocal fact. And... you got there first.   Her next victim will have to learn what  you have already learned.  You can take those lessons and save  yourself from her.

She is not that special.

I got a lot of laughs over the fact that my XW's geriatric Fortune 500 executive sugar/baby daddy got my hand me downs and polluted his gene pool with that whore.  Her DH#3/baby daddy #2 knocked her up while she was still married to her DH#2/daddy #1 who knocked her up when she was married to me.  I laughed about DH#2's predicament and the Karma he suffered and I enjoyed at his and my XW's expense.

Living well is the best revenge. Go live well, and exact your revenge.  She will always be miserable and she will ultimately make the men that make the mistake of having a relationship with her  miserable. You... escaped and no longer have to be miserable as her victim.  Consider her your victim and move on.

It worked well for me in my recovery from that marriage.   Forever she knows that I was a good man, a good husband and that she screwed it up.  

Don't ever take her calls and whatever you do, do not go back.  Keep her clearly tagged as your victim rather than you as hers.  Let her next series of victims enjoy your left overs.

Move on and live well.

There is nothing to be confused about. She is a flake and you are better off. That is me putting it nicely. She moved on very quickly after you split which speaks volumes about her and not in a good way. Either she was already talking to this guy while you two were still together or she is a flake who lacks the ability for real attachment. The first red flag was at the beginning of your relationship when she wanted to get very serious with you while her kid was still in diapers. You dodged a bullet man. She is someone else's problem now. For future reference never put your hands on someone's kid nor tell their parent you don't like their kid. Instead take your SO aside and tell them you do not like how their kid is behaving. If they defend their kid or do nothing then it speaks volumes. But do NOT touch their kid. Anyways you are much better off with this vile women behind you. Be very glad you did not have a child with her or she would be milking you for a monthly paycheck for life. Enjoy your freedom. Once Covid ends join some dating apps and enjoy the company of other women.

The fact that she moved on so quickly is very telling and sort of icky. Is she Covid hunkering down already with her new man and kids too? This is really gross and trashy. Be glad she is your ex. She is nasty. Yuck.

There's a certain type of woman who just goes from man to man. Usually it's because they're financial or emotional parasites. This type should be avoided at all costs.

Quit going for the low hanging fruit. Learn from this mistake, and next time only date women who are self sufficient and have their act together. Bonus if she has NO KIDS.