Feeling like i have to urinate excessively due to ejaculatio

After I drink a decent amount of alcohol (2 to 4 drinks), then if I have sex wit my girlfriend I feel like I have to urinate all of the time for a period of 4 hours to 4 weeks. I have been to doctor several times, and it is not an std, UTI, prostatitis, or because I am drinking too much. Does anybody have any clue what could cause this? And if so, how to stop the sensation of having to urinate all of the time. I know next time no sex after drinking, but it still frustrates me that this happens to me. I would appreciate any help I could get.