ex work drama

So I have been dating a guy for over 3 years, and recently things haven't been great. We've been arguing a lot, and things ended just recently. It's going to be ridiculously hard to get over him, because he's really close to my family, and we were best friends. We did everything together. Also, before we broke up I got a job at the place he works. (That may sound stupid but I've been having a hard time finding a job and I need the money for college.) The boss is really nice, the job is good, I know quite a few other people who work there, and I really enjoy the work. I don't think it's fair to quit, for myself and the people I work for. Why should I give up a great job just because of personal stuff? But I'm unsure how to proceed in working there with my ex. Any advice? I really would like to keep the job, (I'm not going to quit, I think it would definitely be unprofessional) so any advice on dealing with it while working? Thank you guys