But how do I prove it.
Thumper1,
You do not have to. You know what she did and what happened; she knows what she did and what happened. What more is needed? Sure, you may have missed an OM here or there, have the number of couplings not quite right, but as you said; once you know the basics, how much difference do the details make?
You will not, at least while she is in denial and covering her tracks, find the answers you need in your WW. In addition to the healing Library, and SI in general, I recommend the books Not Just Friends by Glass, and Sexual Detours by Hines. Both of these books will help to explain the reasons and dynamics behind affairs.
I did not see it in the other posts, so let me be the first to tell you that her affairs are not your fault. Her As are her issue, her acting out to try and address some internal failing.
You do not need to forgive anyone you do not want to, especially so early on in the process. For now, you do not even know for sure what it is that you would be forgiving, and who all to include. Eventually, you will work your way to acceptance, and maybe or maybe not forgiveness. The OM are not really so important. As I said above, the As are your WW’s issue. The OM were simply available and willing, nothing more or less.
I suggest that you take the focus off of your WW and the M for now, and focus on you and your needs. Many of us find some exercise is a way to fight off depression and work out anger (rage) and resentment. Work on your finances so that money does not become the sole reason you feel you need to stay with your WW if she continues to not get it. Try to save more, spend less, earn more, and set some money aside where only you can get to it. A little bit each month over the next couple of years will build a nice emergency fund.
I also suggest no more MC or joint counseling until your WW stops with the denials and cover-ups, and owns what she has done.
Think about what you want to stay in the M for now while you see if your WW can fix her issues. You probably want no more contact with any of the actual or potential other men (OM). You probably want access to all of her means of communication (cellphone, computers) to verify NC. You want her to not delete any texts or emails until you have seen them. You may want a timeline with who, what, where, and when. You may want the names of all the OM so that you can contact their betrayed wives if married. You may want accountability of where your WW is and proof like a receipt from a store after a long shopping trip. You may want your WW to attend individual counseling, and be able to explain to you why she had her affairs, what she wanted to accomplish, and how she is going to change so it is much less likely that she will have an A again. You may want her to also read Not Just Friends and or Sexual Detours and talk with you about how what these books say applies to her affairs and your M.
If she is unwilling to do the things you ask of her, then you need to think about if you want to remain married to a person who would betray your M, her vows, and then not be willing to move Heaven and Earth to try and repair the damage.
Best wishes and keep posting and reading. It can get slow here on weekends, but you really have found a tremendous resource.