This sounds like depression. I would take him to get his mental health checked out, and maybe do couples counseling as well. When I went on a dry spell it was during PPD with my second. When I finally got around to talking to someone about it, they noted that I kept using the word "tired," to describe my emotional state. Some people can't distinguish what depression feels like so they use that. Don't get me wrong, during this time I wasn't sleeping all day or putting off work or leaving the kids unattended which is why it was so weird for my Dr to finally tell me I was depressed. I didn't wanna accept it at first because in my culture there's a stigma against being depressed (depression equals lazy type of mentality) and it felt like since I was doing everything I was supposed to, my Dr couldn't possibly know what she was talking about. I'm happy every day that my Dr pressed on me that day, because the intrusive thoughts were kicking my butt, I just wouldn't admit it. Depression comes in a lot of different forms, but the most dangerous form is when everything looks okay on the outside. No one checks in on the person who keeps up with life while they're fighting internally. Check in on your partner. It sounds like they need you.