My W cheated with a woman, too. On one hand, it's easier to deal with - there are no possible comparisons between me and the ap. In a sense, her choice of ap tends to show that I'm manly enough for her - it's just that she wanted a woman. If my W had cheated with a man, I might always have wondered if he was more manly than me (whatever 'manly' is...). OTOH, as someone above said, I can't do what ow did, so if that's what my W really wants, we're doomed.
My reading and talking with a few gay men and women say that gay people are disgusted by sex with the opposite gender. That means you have a chance for a good sexual relationship in the future if your W likes sex with you, if she chooses to be monogamous, and the consensus here is, I think, that monogamy is something we all can choose. A bi- person can be just as monogamous as a straight or gay person. It's just that my W has to reject sex with potentially twice as many people as I do.
So D is a choice you can make, and R is a choice you can make, too. So is taking your time 1) to figure out what you want and 2) to observe your W to see if she's a good candidate for R.
R is a lot more than staying together. To R, your W above all needs to change from a cheater to a good partner. That usually needs the help of a good IC.
In your case, your W really needs to look at her sexuality, IMO. Two times for sex spread apart in time make me wonder: Were these incidents truly a matter of bad choices, or were they what she really wants but uses alcohol to stop suppressing her desires? I wouldn't believe what she told your MC unless she really looked inside.
She also needs to look at her alcohol use. Is she addicted? Is getting drunk a pattern that needs to be changed? I know I got drunk in my 30s - I can remember at least half a dozen times. In 10 years. I never allowed myself to cheat while drunk. So I think your W has a problem with either alcohol or sexuality or both, and she can't become a good partner unless she resolves her issues.
To R, you both need to negotiate what your M will be beyond simply monogamous, and beyond the kids - after all, unless you're unlucky, you'll have many years together after your kids move out. Look, you are likely to live well into your 80s, and you can be sexually active that long - with a partner who turns you on. Will your W do that for you in 50+ years? I know you can't know that for sure now, but you can make an educated guess. (And if the thought of sex between old people turns you off now, I assure you that your definition of 'old' will change as you age. )
*****
Most of all, though, you need to heal yourself and figure out what you want.
Healing yourself requires, IMO, the facing the fear, grief, anger, and shame that comes with infidelity and processing those feelings out of your body. It requires figuring out how to stay true to yourself. If you really want R, IMO you owe it to yourself to find out if it's possible - unless you change your mind. If you really want D, IMO that's what you need to do - unless you change your mind.
A lot of adults say they wish they grew up from a broken M instead of in a broken M. Kids know a LOT more than adults think kids know, and they'll know if you stifle yourself more than is good for you. So I urge you not to stay for your kids unless that's really the best choice for you. It may not be the best choice, but it may be for you.
I'm all for R when both partners are willing to do the necessary work, but if your W doesn't address and resolve her infidelities and/or alcohol abuse (or whatever it is that enabled her cheating), R will not work for you, at least IMO.
A good IC can help you here, if you want help.
MC? A good MC can help you with some heavy confrontations. If your MC is looking at your relationship for the source of your W's As, stop as soon as you can, because - as others have said repeatedly, your relationship didn't cheat; your W did. Our MC kept our sessions to my W's cheating.
*****
Above all, know that you can heal, if you learn to process your feelings out of your body. If you learn that, you'll come out of this stronger than you were at the start, and you'll dramatically increase your odds of living a good life in the future, with or without your W.
You are stronger than you think.
*****
BTW, inform OBS - their M may be less open than ow told your W.
[This message edited by SI Staff at 6:28 PM, Sunday, January 22nd]