My husband only seems to like me when we are intimate together.

Married for 12 years now. The first 10 years of marriage was great. I could talk to him about anything. He understood me. He always wanted to be near me. We did everything together. He was my best friend. Every time we walked by each other kissed or hugged me. When we sat together we cuddled. We never fought nor argued.
But about 5 years ago I noticed a massive change. He always seemed uninterested in me except for when we had sex. He stopped kissing me when we walked by each other, it’s like I am a stranger to him. He doesn’t say I love you as often.

The thing that bothers me the most is he only ever seems to be happy when we are intimate, then as soon as we are done he’s back to his distant self. It’s weird because the tone in his voice has totally changed. But when we are intimate, his voice goes back to his happy-go-lucky voice. When he’s not distant he argues with me about everything, and I mean everything! I could tell him I have 5 fingers and he would say “wellll actually… you have 4 fingers and a thumb”. He had to be right about every little single thing and if he’s not he gives me the silent treatment. When I confront him, he always says that he’s the same person he always was and tells me that I’m just crazy.

I forget how it came up, but he has admitted to me that he thought about leaving me 5 years ago, which just happens to be around the same time he changed. When I told him back then and about a month ago that it feels like he was wanting to divorce me, he said thst he wouldn’t even think of such a thing and never ever has. But yet, shortly after that during a conversation he admitted that he has thought about it.

It’s getting to the point where I’m fed up and can’t take his mopey distant self anymore. What should I do?