I tried posting this on another sub but I think it got marked as spam

Throwaway for the usual reasons.

I(24F) have been with my boyfriend(27M) for a little over 4 years now. We recently moved in together 2 months ago.

My boyfriend has a younger sister (20F) who had a baby boy last year and the father isn’t in the picture. The day he was born my boyfriend opened up some savings accounts for him and has been putting money in them and investing it regularly.

The baby’s 1st birthday was a few weeks ago and we went and had a great time with his family. After getting home from the party he asked me if we could talk, he proceeded to tell me that he was heavily considering moving back in with his parents so he could be there for his sister and her baby.

He said it was upsetting to him knowing that his sister’s BD wasn’t in the picture and he wanted to do everything he could to be there for him and be the father he needs. He continued saying that the baby’s party made him realize how quickly time flies especially with young kids and if he wanted to be the good father he planned to be he needed to be there for his “son” as early as possible.

Him referring to his nephew as his son caught me off guard as I’d never heard him refer to him that way before, but that’s not really the issue here.

The thing is I’ve never wanted kids, when we met I told him I didn’t want kids and throughout the years we’ve been together that hasn’t changed. He has also told me that he doesn’t really want kids either. I guess things changed when he saw his sister have to go through the motions of being a single mother and being the loving brother he is wants to be able to be there for her through it all.

I know that this means that I’ll have to be a guardian for him by proxy, and I really don’t want that. I cannot stress enough how much I really don’t want kids, and don’t want to be around them 24/7. He also said that he would feel bad about breaking the lease since it’s only been two months, and that he would continue paying his half of the rent but will be staying at his parents house most of the week in order to be a present “father”.

Ever since the baby was born not only has he been putting money into his savings account but he has been spending basically all of his disposable income on everything the baby needs. He hasn’t bought anything for himself like clothes, shoes, video games, or anything that he would normally buy for himself. He says that he plans on being fully financially responsible for him because that’s what a father does.

I know most people would think that this is such an amazing quality to have, and I’m not saying it’s not but it’s just not where I am in my life right now to have a child or be with someone with a child. I genuinely don’t know if I’m valid for feeling this way but it’s been bothering me. My bestie said I would be the a-hole because he’s doing a good thing.

Do I need therapy? Am I wrong for thinking this way? Should I just get over it and stay with him and live my life with my boyfriend and a bonus son? WIBTAH if I broke up with him over this?