I suggest you take one day to think about what you want, and what you will -- and won't tolerate. Your non-negotiable "boundaries of personal integrity," as they were. Then sit down with your wife, and lovingly but firmly confront her with your knowledge of what she's doing, and let her know from here on out there will be limits as to what you will put up with. Tell her that you are aware of her grievances with you, and that you're willing to work on them, but not as long as there's a third person in the marriage.
The way I put it to my wife was "I know what you're doing with (OM), and it has to stop. Now. It's incredibly disrespectful to me, to our marriage, and to our family." I told her that I loved her, and I was willing to work on our marriage, but I would NOT live in a marriage with three people in it, and I would not be made a fool of.
It took me three months of hard, hard work, but I was able to bust her affair, and she returned to our marriage.
It can be done. But nothing good is going to happen while she is getting some of her emotional and financial needs met by you, and some of her other emotional and physical needs met by her boyfriend.
It's time to set some boundaries. Only YOU know what those are -- they should be gut-level, non-negotiable "dealbreakers" that, if crossed, violate your own sense of personal integrity. Because allowing those boundaries to be crossed on a weekly (and even daily) basis will do more to eat away at, and eventually KILL, your self-esteem that her actual adultery will.
