Instead of giving you an answer, I'll give you this column to give to your guy. If you can't get yourself to do it, just imagine all the amazing moments you could have already shared together. Please, hand it over, and let me know what happens. He could be on a lifelong ego trip unless he matures, which has absolutely nothing to do with his deep feelings for you, who remains safely in the wings until he comes back to earth. If his flirting takes place in a familiar place, excuse yourself and head for the nearest restroom and remain there long enough for him to start worrying.
Some people provoke jealousy deliberately believing it enhances desirability.
Such insensitive behavior is humiliating, demeaning, and a complete turn off. You've probably got men waiting outside of bathrooms all over the country, waiting for you to come out after wondering off. I just finished reading through a number of the letters regarding the issue of cheating, and I thought I might throw out my ten cents. I have already been guilty of cheating twice in my relatively young lifetime. Not to suggest that it is any excuse, but both incidents took place over a period of long-distance separation.