I have since found out the OM is someone that works at her office, is my age, has been married for 10 years, has a mortgage and 2 kids and is in a supervisory position.
Without forewarning or discussion with your wife you should tell the OM's wife the truth about her life. It's the decent thing to do. Chances are OM will dump your wife like a hot potato as soon as he realizes all he has to lose once he wife finds out he's cheating on him. Your wife is most likely just his side piece for the time being. Regardless of whether his wife divorces him or makes him dump your wife, keeping the affair a secret from her kind of makes you their co-conspirator in the lie. His wife may even make him fire your wife which will tick off your wife and could result in a nice little wrongful termination sexual harassment lawsuit. It's not like you can recover your marriage while they still work together anyway so somebody has to leave, might as well get a lawsuit $ out of it in the process.
Is/Was your wife actually clinically diagnosed as Bi-Polar? Promiscuity is a symptom of the illness and any person with bi-polar needs a spouse willing to hold them strictly accountable for their behavior 24/7 even when they appear not to be cycling (because once they are cycling you'll never get them to allow you any power or control). If she is in fact bi-polar, you may be better off getting custody of your daughter and trying to raise her as quietly and as far away from mental illness as you can.
BTW, moving out to "get space" is wayward speak for moving out to continue the affair without your annoying interference and having to feel so guilty looking at you. She hasn't ended the affair and won't as long as you continue to enable her. Last time she did this she didn't come home and beg for you back until she hit rock bottom. She'll wait until rock bottom again and expect you to help her pick up the pieces AGAIN.
IF she's bi-polar - require her to appoint you her legal guardian for all healthcare and financial matters, acknowledging her illness and assigning you the custodial parent of your child before you'll take her back. Basically it's a "I'll only help you take care of yourself but I need you to surrender and acknowledge your illness and put me in charge of looking after you legally and financially". You do this because you love her and Bi-polar cycles get worse with age and often result in suicide. She'll need help avoiding that tragic end.
The internet is 90% complaining and entitlement and I hate it because I deserve better!
