AITAH for not allowing my girlfriend to be a SAHM to HER kids?
I (28M) have been dating this girl Amy (29F) since May 2022. We met through a mutual friend, and things were going pretty well up until a few days ago. Amy has 2 kids from a previous relationship—twin boys that are 7 years old now.

I get along great with them. Amy and I were starting to discuss moving in together and how that would all work out with the kids.
Things didn’t seem like a problem until she asked if we can find a place that I can afford to pay rent on my own in case she becomes a SAHM (Stay-At-Home Mom).
I asked in what instance she would become a SAHM when we aren’t planning on having more kids, and I got a vasectomy 2 years ago that she knows of. She said it’s always been her dream to be a SAHM for her kids and the boys will benefit a lot from always having her home.

She said she knows it’ll be a lot for me to take on, but she would appreciate it if we could talk about it and possibly make it happen as soon as we move in together.
We discussed it, and I told her I’m honestly not comfortable with the idea of me being the sole breadwinner for our 4-person household. I could afford rent on my own, but groceries, bills, stuff the kids will need, etc., I can’t afford all that. And if I could make it work, that would leave nothing for savings. I also said the boys are in school most of the day, and although I agree that any child will greatly benefit from having a parent available 24/7, I don’t think it’s a necessity. I also told her I’ll be stressed out having them all rely on me. She said she understands and that it’s fine. We didn’t speak about it again.

I got a call from her mom about a week after I had the discussion with her. Her mom started the conversation sweet enough before getting to the point. She asked why I decided to date a single mother if I’m not willing to step up for her and her kids. To be honest, this kind of pissed me off.
I didn’t know deciding to date a single mom meant I’d have to happily be financially responsible for them all. I told her with all due respect, this is between me and Amy. She said Amy won’t have more kids because she’s with me and this is her only chance of being completely devoted to her kids, and although I can “easily” afford it, I’m being stingy because I simply can’t be bothered to make a sacrifice. My blood was boiling, and I was trying not to say something rude back. I told her it isn’t her business and cut the call. I spoke to Amy and asked her what the hell her mom was on about.

She said she needed someone to vent to about the situation, and her mum just has her best interest at heart. She said she thought it would be better for me to get her mum’s perspective and then make a decision.
I asked if it would be okay for me to go tell my mom that my girlfriend is asking me to bankroll her and her children’s lives and watch my mom call her names for it. She said I’m taking things too personally and I should’ve expected things to not go great after our discussion… I’m at a loss here.
https://youtu.be/KC72mnmQK88?si=b2tVjWISEyAg_g8L