First, welcome to the forums.
Second, unless you are a teenager (no offense Berserker) can't you come up with a better name than "that fucker?"
You do have every right to be upset. She broke the rules by not using protection. I'm not sure how much communication actually happened after you got back, but it sounds like not much. I mean real communication, not just spleen venting. Why didn't she use condoms? What does she mean by "protecting her relationship" with the other guy? How did "things get strange" to the point where he rejected her?
Ignoring something never made it go away. If up until this point you had a communicative relationship, then why did that stop? It sounds like we may be missing some details though maybe?
What were the old coping mechanisms and why are they gone?
Change happens. She has found out that she would prefer a polyamory relationship as opposed to polyfuckery relationship that has been the norm up to this point. Do you love her enough to try and do you love yourself enough to know whether you can live with this?
Give it time, talk with her more.
Life is about the journey and not the destination,
so what better way to know life
than to wander all the roads and paths set before you.