@john5678,
I don't want to be judgmental, but a few more details would help. Do you still love your wife, do you have children? If so, you may benefit greatly from couples therapy. If not, you may need to seek therapy for yourself to get back on track. I'm not suggesting medication, I don't know how long you have been married, if you were happy or content until you met the current woman, perhaps you can rebuild on that foundation.
As far as the other woman, she still has an exciting, secret her husband and children don't know about. But you are living in your old flat. If you were a woman I would tell you to run as fast as you can. Bottom line, you don't seem very happy right now, you may be worrying about what your family and friends think. Nobody wants to hear, "try counseling", but you can talk to an impartial 3rd party who can help you. If you don't click with first one, find another.
Consider this, you are expressing you have a difficulty in your life and you have
taken a big first step. Good luck to you.