Unpacking what it means to be a stepmom

This is my circumstance: I have four stepchildren. One daughter is medically fragile (I believe that’s the technical term; she cannot fly in an air plane, cannot swim, has multiple tubes in her airway and stomach, 24/7 nursing care).

I have an amazing husband. I married my husband because I love him and I think he’s a perfect partner for me. When we were dating I told myself: I can’t rule out a really good man for me just because he has kids from a previous relationship. He’s everything I always wanted in a partner and we want the same things in life (I could go on, my husband is great). And then I met his kids, and I thought they were great too. I was actually shocked how easily kids could love you/ how easily you could fall in love with kids (more on that later). My husband’s kids, my step-kids, are really good, kind, kids. I have fun with them and mostly think/feel positive things when I’m around them. When they’re not with my husband and I, it’s a different story.

Lately, in doing my thought downloads and models, I’m realizing that there’s a lot to unpack – I have a lot of negative thoughts about what it means to be a stepmom (its extremely hard work, no one would voluntarily choose to take care of someone else’s kids, they will never respect me, I’ll always feel like an outsider to the family, stepmoms are looked down upon by society, I’ll always come “second” after my husband’s kids) and helping to raise my husbands children (kids are hard work, all of my money, time, energy, will be spent taking care of them, he has a really complicated daughter, I don’t even like kids that much, never have- but I want (we want) biological children)

Unintentional model:
C: stepmom
T: Being married and a stepmom is far worse than a marriage where there are no kids from a previous relationship
F: shame
A: not fully step into my role; push the kids away; not fully integrate into my new family
R: unhappy family life

Intentional model (I am struggling here – more below)
So for the intentional model, I started thinking wait a second – these beliefs are just that – Why do I have to think being a stepmom is a thankless, self-sacrificing, harder than the hardest job ever that no one wants to do? Why do I have to feel shame? I don’t. Why do I have to think “I don’t like kids that much” or “kids are so hard”? I don’t – I want to really believe things like: I enjoy my husband’s kids. and Being a stepmom is an honor.
That’s such a big leap for me, though. I’m really struggling to find a bridge thought from both general/ role position as a stepmom and also being in the position of helping my husband to raise his kids. All of this is making me think that I should have never married my husband in the first place because I’m struggling so much with accepting myself as a stepmom and parenting his kids, even though my husband is so wonderful. Do you have any bridge thoughts to offer? Or thoughts I can try to get to a more neutral place?