Should I have a saying?

Okay a small background story..

I’ve been with my boyfriend/baby daddy for about 3 years , we were best friends before we started and I knew he was going to have a kid .. whenever I met him I knew he got his baby mama pregnant but wasn’t with her way before I came into his life ..

Anyways , proved to him that I was the only friend thag was going to stick around once the baby came out (still being proved ha) and we became a couple ..

Anyways .. I got pregnant while on birth control and we had our daughter .. and he got 2 kids in one year .. lol yes it sounds extreme but it isn’t as bad as it looks ..

Anyways .. 3 years later we are still together ; living together and thinking about marriage . There’s no beef between me and his baby mama bc she moved on with her life and had another kid by someone else..

So here I am .. being a stepmom helping him raise his son since the very start and i asked him if maybe one day I could get him if all of the sudden he has to go to work on the day we are suppose to have him .. and he says no .. that he wouldn’t send anyone to get him..

But I’m like 😒😞 whyyy.. like i feel like I have a saying and maybe o can ask his baby mama if I can pick him up one day so he can hang out with his sister (my baby)

And he said no cause we aren’t married and whatever..

So idk I’m a bit butthurt bc shit I has been 3 years .. o feel like he’s my son too although I didn’t birth him I’ve raised him .. to putting him to sleep to changing his diaper to everything .. I have so much love for his son that even when I got to Walmart with his son and my daughter they think he’s mine . And instead of explaining that he’s not mine I’m just like thank you! They’re 11 months apart and blah blah blah ,.

Okay so question ; should I have a saying in this? Should I speak to his baby mama to see if she’s okay with me getting him some days or to even surprise our baby daddy at work with both kids?? 😐 idk