She does not want you in her private life. So, stay out of it. And stay out of her house uninvited.
This is all you need to know, regarless of what she is doing with whom, you are NOT in a monogomous committed R. You cannot change that right now.
Base your choices on those brute FACTS. The details of the kinds of sex acts shared with whomever are irrelevant. They are only relevant IF there is an R that includes monogomy and commitment that needs to be worked out. There is not such an R right now.
