Dating: Acting weird post hook-up?

I think a lot of people are convinced that sex doesn’t really change the dynamic of a relationship – casual or serious. Then they try to figure out why the person they slept with is acting so awkward all of a sudden. Sometimes sex can alter the way a person treats you. What do you do when someone starts acting weird after you hook up?

For example, my friend Linda has had fewer texts and calls from a guy she is seeing. Immediately after they hooked up he was clingy and barely left her side. Now he is distancing himself from her with no explanation. She thinks it is because they hooked up.

Have you ever been in a situation where sex totally changed how you behaved and felt about someone?