i feel that i love and miss the girl in my secret relationship more than my wife

ive been married for 20 years. we had a period of separation when she had to go work abroad. during that time i seem to have drifted away from her not just because of the distance but with little things as well. i got into a secret relationship and when my wife came back she seems to know that something is afoot. i lied when confronted about it and in turn put my secret relationship on the rocks to the point that i called it off. now i dont know what to do. i feel that i love and miss the girl in my secret relationship more than my wife. sometimes i cant even bear to be with my wife at all. help!!!