I’m sorry to say it, but it sounds like something like intermittent reinforcement - you mention it’s cyclical in nature? If he’s nasty, then nice/back to “normal” (including pretending something didn’t happen), it sounds manipulative to me. I’m not saying he definitely is, but his behaviour, and the fact there’s a pattern in it that you’re picking up on, doesn’t sound right.
Definitely agree with you having individual counselling, it could prove very helpful and be a source of support for you. Don’t be afraid to have a few consultations if you don’t feel the first therapist you meet is right for you.