He hardly ever wants to have sex

Maybe my sex drive is just too high? But he is happy with once a week even less . It's getting worse every day. He says mine is u usually high. I'd be so happy with him if he just wanted to do it more. It is good when we do it! We fight about it all the time. He says it's so unattractive when I keep whining about it, and that's just his sex drive! In fairness we are together three years and he's kinda always been like this (maybe he did it more at the start,but then it dwindled). Now we have a baby which means it's happening even less. He could come on to me when she's asleep but he doesn't and then says "oh but we have a baby it's not as easy to anymore"

I know 100% he's not cheating or texting anyone else. I know this is just his sex drive but I feel so undesirable and I've never had this problem before! I feel frustrated all the time! I honestly feel like getting into a no strings attached relationship just for casual sex. (Obviously I could never do that!) when we do it it seems like a pity fuck on his part which means It's not the same!!! He knows how depressed it's making me feel but keeps telling me to stop trying to change him! anyone else ever in the same situation???