This is interesting, and frankly, kind of new to me. I don't want to hijack this tread, but could we have a separate discussion about this? You would do mankind a service I think.
Back to soxx:
I'm not a shrink, but I think this is a clue. Maybe you got too familiar and confident in your relationship. Maybe what you need is some risk.
How about having sex in forbidden places? You could have a quicky at your parents' house at your next visit over, or even better, at his parents' place. Or in the men's bathroom of a five star restaurant. Or in the elevator of a government building (check for security camera's first!). Something I would like to do once is make love to a girl while she's on the phone with her best friend, without letting that friend know.
Now perhaps you don't need to be physically in the forbidden place. Maybe you can imagine that what you do is kind of wrong. Maybe you can convince yourself that someone is going to burst into your bedroom while you're at it. Leave the door ajar next time.
You could also imagine that you're married to a rich old man, and that you're having an afair with your partner. If you're afraid he might get jalous (of himself? Could happen) you don't need to tell him. Your toughts are private after all, and I'm sure he'll appreciate your new found vigor.