My friend pretty much experienced part of what you did. He kept accusing her of having an affair with all sorts of people --- including a priest. But she never suspected him of having an affair, and up to the time she left, she never knew if he did.
If you're struggling with affair number 3...maybe it's time you start thinking of moving out, and moving on.
I think you're familiar with the saying: Fool me once, shame on you. Fool me twice, shame on me.
