Okay, read your thread and see that W told you she wanted a D. So as of right now, where does the M stand? Has she seen a lawyer or made any other attempts that would look as if she's preparing to leave the M?
You are having sex with her, knowing she had sex with OM. Was she tested for STD? Had your sex life fizzled out before she took the cruise and slept with OM?
I'm mostly asking questions here, not telling you what to do. However, I want to give you a word of caution about her easing back into the MR without making a commitment to do whatever is necessary to have a healthy and strong MR. The board has seen this played out many times in other stories. When a H tries to better himself (which is good) and the WW is friendlier for awhile......but still holds the "I want a divorce" over his head.........it can tie him to that roller coaster. One day he thinks things are better, but then his W doesn't want to give up her sources that help feed her waywardness. She does nothing to earn his trust, continues her disrespect. In order for him to be able to live in the M........he tries to turn a blind eye to her unacceptable behavior and activities. He will repeat things he picks up from the board and try to wear a convincing front by saying he can't control what she does (which is true) and he's doing x,y, & z for himself, yada, yada. He doesn't truly heal, and she remains in her wayward status. The couple eventually falls back into their old slack ways and the W continues to keep the lines hot looking for the next OM.
You can go for the rest of your life living just like things are now. It may get a little better. Of course you cannot cross your W b/c she holds the power in this relationship. Being wayward and her making no effort to change, or even being remorseful........ things may get worse between the two of you. How many affairs (EA, PA, IA) has she had since you M her? You don't seem too phased that she had sex a few times with the guy on the cruise. Is that b/c of the length of time it has been (before last Thanksgiving)?
I think you are trying hard to stop the divorce train. From the view of other LBS, you may look as if you are doing fine. ( I agree you need to seriously GAL. ). IMHO, I think she will hold the divorce sign over your head, and whenever you say a word that doesn't set well for her.......she'll pull out the sign, b/c that's her leverage. She has seen how it's worked to whip you in shape.
You mentioned her childhood, can you tell us what she experienced?
Have to run, but I'll check back later.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!
