How to diagnose Erectile Dysfunction?

Following is probably the most interesting question you were asked.

I moved from the U.S. to Amsterdam, Netherlands over one year ago. I am a single and so I go to Red Light district in Amsterdam a lot. I didn't have any erectile disfunction at the beginning, but gradually my erection was getting worse. Now after over a year, my erection is not hard enough to penetrate.

I know it is not physical problem because I got erection during sleep all the time and have good health in general.

My questions are:

Did my frequent visits to Red Light district cause my erection problem?

If yes, how could I treat my erection problem?

Thank you very much for your advice.