Her adultery feels like the one true deal breaker for me. I can't get over it. I read some thread where a guy's W caught an STD and he still kept on, and I read over & over in archives and from vets that swear repeatedly: the OP means nothing. Nothing.
I'll wager that was my thread.
Here is the deal, your BD is still fresh and you feel betrayed ... even more so as she is doing it right under your nose and by her actions she in a sense is rubbing that same nose into it. For me when I found out about the A I was LIVID ... like you that was a deal breaker, over time I can not say when/how or why the sting was not as painful and my desire at the time to have my W and family back overrode the 'deal-breaker' of the A. Thats how I landed on DB some several months after BD.
That being said you do probably need a good dose of Boundaries. You can not control her, but you need to place some boundaries in to protect yourself. Her using you till she is set to jump into the other tree would not work for me TBH ... you may want to give this some thought. ... just my 2 cents.
