I recently reconnected with an old acquaintance(opp sex) we, became close and were very supportive because we were both passing through hard times, his was a breakup and mine was work/some other losses, well stuff happened and we had sex, we talked about it and agreed nothing was to come of it, the friendship was good. Suddenly he made up with his ex, and totally cut off from me, it went from a hundred to zero, I want him to be happy with whoever, but his attitude just totally changed and kept me questioning what I did that made him totally detach, and not even speak with me again, took a while to be over the hurt. but I still wonder why people change that fast. However i wish him well.