My BF's Wife Is My New Boss, Should I Be Worried?

From LIB ---> I took a job recently and realized my immediate boss is my married boyfriend's wife. I've had confrontations with this lady in the past, so imagine my shock at finding out she's my new boss.
But the weirdest part of this is, since I joined the company, she has never acted like we know each other from the past. I'm worried. 

So my question is this; should I also act like all is well and pretend like I don't know this woman, or should I just move on, leave the company and find work elsewhere? 

As for the man we both share, I don't see us ever breaking up. And where I work is a place anyone would even wish to be hired as a contract staff. Please advice!!