Is he also poly? How well does he accept that you have gfs? Does he love you?
Very few people can stay in a committed relationship and feel okay about their partner being intimate with other people. He might have strong feelings for you but he finds it hard to accept that you have feelings for more people than just him. That in turn can cause a lot of distress and lead to unusual behavior. I might be wrong, there might be something else bothering him. Or you might be right and he does have a disorder. Talk to him, see if anything is bothering him.
My problems were caused by work. When I started having serious work-related issues I exhibited a lot of strange symptoms that were previously uncommon to me, like falling asleep during seminars or regular basis, distracting myself with problems not relevant to m work, getting involved in projects not relevant to what I am doing and I started getting this growing feeling of losing my mind due to inflated anxiety.
Talk to your man, see if anything is really bothering him.