How's this for awkward? When I was 16 I dated X for a couple of months. When I was 28 my Dad married X's mother so my ex-BF is now my step-brother.

I don't see much of my steps - they live on the other side of the world and we were adults when our parents married so we have never had a close relationship (as adults). They're decent people and I think if I saw more of them we might be better friends.