Boyfriend not supporting my BA

My boyfriend is not being supportive of my want/need for a breast augmentation. I want one so badly and have finally decided to start saving. I have very small a cups. I want a medium to full c cup. I’ve decided. I asked him if he would leave me if I got it done and he said no but he kept telling me im wasting my money, I’m ruining my body, etc. I’m doing this for me but I don’t see why he’s not being supportive. He always looks at big breasted women, why isn’t he happy? :(

I’m worried he’ll end up leaving me.