You are still a young woman and IMO have your whole life ahead of you. Do you want to travel (when it's possible again), develop your career, follow new interests?

I think you took all this on at a very young age and consequently have missed out on other life experiences. From what I read in your post, you are feeling trapped,  but afraid of life "on the outside "

I believe you know what the answer is...

He wants to just continue his old life with a new wife.  He wants one big Happy Family.  You want him to start over from step one.   Dataing you, doing adult child free things,  weekend get a ways, making love all day, vacations, alone time.  Yoir big wedding , shower, honeymoon trip. 

You want to start your own family with out SD there to remind you of his past life.  

Him saying ,  you knew I had kid, no one from my family will want to come to a second wedding,  The child comes first, SD should come on honeymoon.  To legoland, Santa workshop,  not Hawaii alone. 
 

I would think twice, if it not that good now, and this is the fog time,  this is the best it's going to be it's all downhill from here 

Depression often starts when we are living the wrong life for our welfare and happiness.  Reading through your account, there are, in my opinion, too many negatives, and not enough positives in this relationship, for it to work out in the long term.  If I were you, I would end it - you both seem ambivalent about the relationship, and he is actively hostile sometimes.  You are plenty young enough to find someone without all this baggage.  

"When a man marries his mistress he creates a job vacancy. But when a mistress becomes a wife, she doubles her workload"

Why are you putting up with his crap? He flirts with women online and you think that isn't a big deal? Really? Is he married or not? Is he committed or not? Ever heard of emotional cheating?

I don't care how bad things were at work, that is NOT a reason to tell you to pack and leave. He apologized the next day? Of course he did, he had had time to think over what a loser he is and how much he needs you to prop him and his daughter up.

What's the story behind the drunken arguments? What's the cause? Who's the drunk?

I'd grab this opportunity to leave, to take the time and space to think through what I wanted for ME. Sometimes you have to put yourself first and this is one of those moments. You are at a pivotal point in your life - if yoiu don't work out what you want now, you could have regrets for the rest of your life ... especially if he's lining up his next conquest.

Put you first and see where that takes you.

Good luck.

"Just flirting" is not innocent, especially if it's ongoing and with the same women. It's a betrayal, make no mistake about that. If he is committed to you, then he knocks off the "flirting." He may dismiss it as innocent fun, but the mere fact that it bothers you should be enough for a committed partner to put your feelings ahead of his own amusement. Do NOT minimize your own feelings in this or any other situation. You do yourself no favors, as you're learning.

Take a step back. Take some time to yourself to see if this is the life you want. I highly, highly recommend individual counseling to help you sort through this. You have some work to do.

There is a reason that "if they do it with you, they will do it to you" is a saying. I've seen this play out time and time again with family and friends' relationships. Hell, my own "husband's" mistress thinks that he's faithful to her because he moved out of my house leaving me and my daughter. She thinks they're going to live happily ever after. Little does she know that he still showers me with gifts, compliments, and affection and tries to sleep with me all the time. Nor does she know what I know about all the dating apps he's on and how many women he is stringing along. She thinks he's a "good man" too because he's handsome, charming, kind, funny, adventruous, generous, and successful. All of those things are true, by the way. It's just that he is fundamentally incapable of being faithful to anyone. I'm keeping his secrets for now because I'm just waiting for the right moment to dump all my evidence on her and shatter her world like they did mine.

Anyway, I digress. I'm aware that my experience has really jaded me to the possibility that a cheater can reform. I'm sure that there are some out there who can. But first they have to believe that they're doing something wrong. If given his history with you, your husband thinks that it's okay for him to flirt with other women, that is a huge red flag. Especially if you've told him that you don't like it. If I were you, I would count my blessings that he is revealing his true colors to you before you have children with him.

My daughter is the very best thing in my world, but if I'd known about my husband's infidelities before she came along, I would have saved myself YEARS of turmoil and heartbreak by leaving him sooner. By the time I found out, we had DD and I really believed it was best for her to keep our family together so I forgave him repeatedly, all the while just tearing myself up inside and becoming more and more depressed. Thanks to an excellent therapist and a good amount of time, I can joke about it now and at this point I'm more angry than sad, but I can tell you that the pain I've endured is indescribable. I hope you'll trust me when I tell you that you don't want to wait around until he actually has an affair (if he isn't already). It will hurt you more than you think is possible. If you love yourself, you'll wish him and his daughter well and leave sooner than later. Don't waste any more time raising a child who isn't yours for a man who doesn't respect you. The idea that there is some big payoff for martyring yourself like that is a fairy tale and you are still young enough to find someone who will treat you well.