Dear Dbambs, welcome to Psych Central. A friend went through this with a gay wife. It is a tough row to hoe so to speak.
Usually the gay wife is not just seeking a partner for romance but also a whole way of life. Divorce is a difficult choice when there are children because there are still bonds as you see with your current partner.
Her gay husband may be the safe confidant that she always wanted. It could be her fantasy relationship compassion without romantic entanglements.

Divorced people have issues. A therapist (t) or psychiatrist (pdoc) can be a help. Unwinding something like this can be talked about but a therapist can help chart a course.

Check out the other forums - they may help.