Don't shit where you eat... but what happens when it follows you to the table

So I was thinking about all the couples at my work and that have worked with me and I always think to myself , what happens when they break up and they still work together? SUPER Awkward. As a rule of thumb i really try to just not even go there. I've been there done that (i'll tell you about him another time). wasn't fun. But there was this one time that i did hook up with someone who eventually ended up working at my job for a little. That was really odd. Sometimes he annoyed the crap out of me and sometimes i didn't mind chatting with him because there was no one else to talk to. He was definitely a pervert. By the time we were working together he had a girl friend and constantly he would make comments about taking break together and going out to my car and giving him head. I would just brush it off because i'm not one to make a scene. but there were times where i was so tempted to say something to a supervisor but decided against it because I knew he really needed the job. I mean perhaps that's not really my concern. He should know better. But I just couldn't do that to him. So instead i just dealt with the uncomfortableness.
But what does one due if someone you have dated or hooked up with starts working for you??  I mean in this economy people need to work and it's really hard to find a job so you can't just get up and walk out. Is it right to allow someone to make your work place uncomfortable?? No not ever. But i'm just the kind of person who would just rather deal with it so that person can provide for their family.  Now if that person didn't have ties to extra people like children and a wife I think perhaps i would be less hesitant to blow the whistle and say something. But for me anytime i've had to work with someone who made work uncomfortable  they always had extra baggage.

So no matter how cute a guy is at my work i'm just not going down that road again and hopefully i don't ever start working somewhere where i run into someone i've been with or someone i've been with starts working at my job.