Anyone had a child from a previous relationship? !!

Vay • Mommy of Three ♥️ Laniya, Kayden && Kaylani
I need someone's opinion, I don't wanna over react, but my daughters father had 6 kids by 3 different women. My Daughter is the oldest. Any way his ex used to involved all of the kids in everything. She loved my daughter and I loved her for loving her. Anyways my daughter had complained that his gf only takes pics of the other kids and don't take pics of them. Anyway they got family pics done them and their 3kids that they have together. My daughter seen the picture and started instantly crying . I feel if your in a relationship with someone then you should accept all the kids. And family pictures should be with all the kids. It's not like he's unable to see them but she just doesn't treat them as hers and I can't see how's he's okay with that. I would never take pics with my fiancé and son and leave my daughter out. Am I over reacting ? My so and I took pictures with my daughter before I even  got pregnant with my son he loves and even calls her his daughter . Am I wrong for thinking she should treat the other kids as hers? I could never date someone with outside kids and not treat them and love them as mines