Hi Doctor. I'm A 30 Year Old Male. I Tend

Hi doctor. I'm a 30 year old male. I tend to get small cuts on my penis after sex with my partner. I also experience a burning sensation during intercourse. We have both been tested for STD and HIV (both negative). I have been to a doctor and he suggested that it may be some sort of eczema. So I took some oral medication and recieved a topical cream. The cream helps with removing the cuts on my penis. I even went as far as having sex with another woman just to check if the problem occurs with other women. Sadly the matter is exclusive to my girlfriend. She has experienced some vaginal issues (mainly thrush) I had hoped that after her resolving that issue that the burning sensation would stop, unfortunately that's not the case. It kind of feels like her vaginal fluid is acidic and that's what causes the burning and cuts. Please help.