compatible?

We've been together 13 1/2 years. Of that, I've been going to counseling for 8, which means we've been miserably unhappy for at least 9 years, if not more. Things have only gotten worse over time and it doesn't look as though we will be happy, really happy, still for a while. Perhaps his affairs are just a reflection of the fact that we are not meant for each other. He used to talk about how heloved his first wife, they just couldn't live with each other. Maybe it's the same with us?