I would say that sex is overestimated in a wrong way. It is one of the deepest desires and in case you are not conscious about it, you can live your whole life being rules by the desire. And surely people know how to use this to control other people.
On the other hand, sex can be a strong transcendental experience. I am not saying that there are no other ways comparable to sex, but every experience is unique.
I wrote a post about Yin and Yang. Sex is a great way how to see the principles dance. And there are traditions using sex for spiritual awakening. But I am basically just saying that you don't have to overestimate it, but also no need to underestimate it :-)
Taking a step back, what you are talking about here is really a wider topic of getting attached to anything. Really easy to get caught in the trap. As long as we are attached, there can be no peace. Perhaps I could write a post on the topic :-)
Attachment is problematic. It's necessary and trouble at the same time. This goes back to dependency. Great insights on sexual stuff. You're probably more normal than I?
Depends on the metric you use for being normal I guess :-)