He doesn't think I'm attractive anymore

I don't know what changed. Or what went wrong. But the only way we have sex anymore is if I initiate and sometimes I feel like he does it begrudgingly. He hasn't initiated sex with me in months. It's not even worth having it anymore because he only lasts a few seconds due to not having much sex in the first place. I dyed my hair, and gained 20 pounds. I didn't think that would make him never want to have sex with me again...