Unknow penis discharge

[junior1976]

Thanks in advance for reading my post. I’m 33 yrs old married man that have been having this clear sometimes green discharge on & off with no pain or burning symptoms for about 2 yrs. I saw my urologist which had done a urethra culture, cystoscopy, urine test and they are all negative (no STD) for Chlamydia, Gonorrhea & Gonococcal urethritis or any bacteria so he suggested that I dont milk or squeeze my penis after passing urine if I do & diagnosed me unknown chronic urethritis for non-gonococcal or non-specific urethritis. What really weird about that is sometimes I have no discharge at all. My PCP gave me some antibiotics just to see if it’s going clear that but no result. thanks