DEAR ABBY: My husband of 2 1/2 years was having an affair with a much younger woman for what I believe was about two months. I never suspected. It ended because he got caught. I was devastated and asked him to leave that night. He always seemed uninterested in sex, and when we had sex, it was quick. He had difficulty performing so, of course, I was extra shocked. We went to marriage counseling, which didn’t help. I decided to stay with him, but I’m miserable. I can’t get over the fact that he cheated, and I bring it up all the time. I no longer trust him and wonder why I stay. I love him and I…