Seeking expert testimony is a sign of strength. A personal relationship with a caring professional is proven clinically effective.
I believe I can help with your situation.
I understand that this is something that happened when you were drunk and you do not feel that you are gay. However, you feel so much guilt over the incident that you keep punishing yourself by sabotaging your relationship.
As soon as you text a woman asking them about this, they will think that you ARE gay, and may also think that you have some sexually transmitted disease, and will also thinkg that you are not a good potential boyfriend or safe lover.
You are shooting yourself in the foot with this obsessive thought and the corresponding compulsive behavior. This is obsessive compulsive behavior and you can stop it either by getting therapy, or quite possiblyo using a good self-help book.
Let me suggest an excellent one for you which you can order from amazon.co.uk
If you can do it on your own, stop the letters. If you cannot, this book will help you.
You will be fine. You are not gay, it seems, so try to move on with your life and get over this one-time incident and don't let it define you.
Elliott, MAE, LPCC, NCC, CCMHC