No S E X with OWs until you directly, clearly, distinctly tell W that you are no longer in a committed monogomous R with her.
Doesn't matter what she did. You seem to be living with her as your W. Thus, no S E X outside M without fair warning.
Another fair warning, this one for you: Unless I'm missing something, you aren't anywhere near done with your M. Thus, sexual Rs with other women at this point aren't going to turn out well for anyone.
