He hasn’t shown interest in getting to know your boyfriend. If you guys hang out, he leaves the second your boyfriend shows up. That’s probably because he’d feel guilty about his feelings for you, if he befriended your man.

If he is divorced or was with another woman for a very long time, you naturally developed a friendship with her—a friendship that still exists. Imagine how betrayed she’ll feel when you marry her ex.

Friendship plus sex is a pretty rock-solid formula.