Having to work with exwBPD and her new supply , need help

[WorkisHell]

Hi everyone, first post here and very thankful to have found this forum for help.

I’m in a situation where I just got discarded by this girl with diagnosed BPD I was dating since April. It was actually more of a intense friends with benefits situation, since she is a coworker and when we started texting in January she actually had a boyfriend. Fast forward months of flirting and sexting she broke up with him and we started dating and being intimate in April. At first was very fun and the love phase too. Sneaking around the office and kissing each other ( we were in different departments so no biggie).

I got transferred to her department coincidentally last June and at first it was ok. Work was fine, the relationship too.
I also enjoyed starting to hang out with her and her supervisor ( he is our age) after work. Having drinks between young people, we were like 3 young buddies. But I did notice her enjoying his presence more and more and she started mentioning how nice it was to smoke with him and hang out with him.and I started feeling jealous. Especially since she had many irrational fights with me while I was doing everything I could to keep her around. But just because this guy smoked weed with her, he was suddenly the coolest. 

Long story short, she started being shady via text, avoiding me but still telling me she loves me. I eventually learned she has been screwing with the other guy on the side (her boss) and when I confronted her she denied and blocked me and said to leave her alone. 

I have to deal with seeing them everyday at work , I’m now a ghost to her, she hates me for revealing who she really is, the other guy has no idea I know , nor does he know about me dating her previously.  How do I deal with this ? Changing jobs is no option . I have to deal with seeing her clearly love bombing him and My self esteem is on the floor , thinking how could she replace with me with no warning or at least telling me she didn’t like me enough… she also knew I’d been cheated on multiple times and did exactly that.

how would you deal with this ?