Don't call me on my birthday and I don't care. I have too many Blessings in my life to worry about petty people. It sounds like its exhausting to be her. 

Wow is this from the SD playbook? My SD15 doesn't acknowledge me for any holiday unless I do it first but she always does the 2 days late thing for DH like clockwork. Then it's the same exact message, texted, no VM because she doesn't actually want to talk.

So sweet, innocent, loving...and busy. Yet whenever I see her the phone is always in her hand. Busy my a$$.

To figure out all their shenanigans isnt it? Ive netflix to binge.

Yes, it does sound like shes playing some mind game.

Teenagers, doesnt she have better things to do? Other havoc to wreak?

I judge people by how they act, not what they say.  So, when SD61 stole from us while living with us (specifically my possessions) and made our lives hell with her lying, manipulation and drug use, that told me all I needed to ever know how she felt about me.  So, now I hear "I love you" and receive dollar store gifts from her but it doesnt register.  I dont discuss her with DH at all, neither her faults nor the gifts, nothing.  If she acknowledges me in any way, I say thanks and I'm always polite and civil.  Do I trust her?  Do I believe her?  Would I confide in her?  No, no and no.  The minute I hear she's coming, I immediately  hide my purse and try to think of a way to be unavailable (nap, bath).  I am trying to keep things livable while DH lives.  This is his only daughter  and I know she will be in my life while he lives.

Mines have never bothered on my bdays and probably dont even know when it is. When i was somewhat engaged, i hosted bday parties and gave them gifts. They also dont care about their dads bday but he doesnt celebrate it. I have never celebrated my bday since I got married, nor anyone outside of my family or coworkers ever wished it. In fact,last year it was completely ignored.

I usually try to travel or go somewhere for myself and buy me my own gifts. I figured since no one in my home celebrate bdays or care to remember them (supposedly) it doesnt mean i should punish myself

Hell would freeze over before any of the steps call me to say anything nice. They actually arent allowed to reach me because BM doesnt want them to contact me for anything but pick up or drop off or when their father is not responding. I got tired of getting texts about forgetting stuff or can you ask dad to call so I blocked all of them, im not anyones secretary.

Your older SD is a complete B, but at least she's honest about it. In contrast, your YSD is such a coward, trying to keep in both her sis/SIL's good books AND daddee's. So pathetic. 

It's misogynistic to say, but so many of the problems in step life come from women with daddee issues and the men who are too scared to shut their poo down.

So in other words your DH got upset that SD didn't phone you on your birthday, he called her the following day and then she sent you a message wishing you a happy birthday.   She's only done this to say to DH that she did call you and then he's happy.  So it's really nothing to with you, and only about his and her relationship.

If you matter to someone, it doesn't matter how busy they are, they will make time to contact you even if its a text or a call for a minute, they will do it.

now if you don't matter and aren't respected, appreciated or valued in their life, they won't make an effort to contact you. It will be the typical "sorry i'm busy"

this is why my husband doesn't say hppy birthday to his 3 kids from exwife but will always remember for me and our 2 kids together. Because we are important to one another and value/appreciate and respect one another.

if your husband mattered, sd would have messaged or called a simple hopy birthday

If you matter to someone, it doesn't matter how busy they are, they will make time to contact you even if its a text or a call for a minute, they will do it.

now if you don't matter and aren't respected, appreciated or valued in their life, they won't make an effort to contact you. It will be the typical "sorry i'm busy"

this is why my husband doesn't say hppy birthday to his 3 kids from exwife but will always remember for me and our 2 kids together. Because we are important to one another and value/appreciate and respect one another.

if your husband mattered, sd would have messaged or called a simple hopy birthday

It's time to be jolly, so jolly that you forget about SD. And guest what no gifts for her. You forgot....

This is being disrespectful to you,  your DH should not be disappointed, but should be a parent and call her out on it.  For being a "B" and disrespectful.  There should be consequences for her actions 

This is what she does, hoping I'm sure that I would say some derogotive things about her and not calling me on my BD and DH being all upset with me for it etc... in fact I'm sure she left it so late the following day deliberatly just to give me lots of time to complain about her disregard for me and so on, hoping I'm sure DH & I were arguing about it with him defending her as always and saying she must have had something going on, so that when the sweet and innocent voicemail going on and on with the big apology and best wishes etc.. etc.. would not only make her look the little wonderful darling but me the nasty evil SM just waiting to pick on her and trash her 

I really think you are reaching about all of this. She just didn't want to call you, but then your DH called her out, so she did.

You're so sure you know her motives but I honestly don't think she gave it that much thought!

You know her better than the rest of us.

Go with your gut. You know she is a B. You know these types of SD's always have something up their sleeve. Youve lived it. We can try to project and explain it away, but truly you know her. Wrong or right as to SD's motives, the end result either way is that she is a self centered B.

Be glad that it bothered DH and he dealt with it.

I know its dang hard to get these toxic shits out of your headspace, I get it. Redirect your thoughts to a more positive tone. DH did good. Keep reminding yourself of that.

Honestly I'd be so shocked if my husband agreed with me like your's did and called her out on it. Instead I get gaslighting.  My husband really has it down to an art. 
As I've pointed out SD did not come for Christmas even though she traveled to the area. DH met her the Monday after and for the past yr hangs his hat on that. That she did celebrate and get this. I could have joined in the fun but it was me that snubbed his daughter because I chose not to go even though I was off from work. NOT TRUE.   I've heard this all year and frankly he had me believing. 
So I checked yesterday. I worked that day and told him. His reply?  Oh it must have been the day after New Years. INFURIATING!!  
I let him have it then and there. He will never never take my side. I called him a coward.  I said he's afraid to  be anything than sunshine and smiles with his daughters. Instead he gaslights me!!  He really was furious but so was I. 

shes got that blossoming thing where she learned to deflect, and gets the "little girl" high voice. Shes been put on the Golden Child pedastal for so long, shes got the whole thing dialed in.

My SD does the exact same thing.  I'm the one that has purchased all of their gifts,  sent her a fruit bouquet for the 1st birthday that i met her (from ME, not dad).  I've NEVER received so much as a card,  even though she talks about her 6 figure income.  I'm just DONE.  SKIPPED HER BIRTHDAY THIS PAST YEAR.  She gets her dad expensive gifts & disregards me completely.  It would be different if she had a good relationship with her mother,  but she hated her mother.