16 year old, 20 year old, & his girlfriend

I just recently started a job, and of course the first person I noticed is my 20 year old manager. I'm sixteen. He is amazing. We flirt all the time and text 24/7, but he has a girlfriend. Basically he told me he couldn't do that to her considering they had been together over a year. So he told her that we text & now she stalks me all the time. I guess I'm glad he had enough courage to tell her & not keep it a secret. She hates me & I apologized to her, but it didn't work. He still flirts with me at work, and we talk like couples do. He even told me that he gets feelings for me & how beautiful I am...but he cant leave her. He says the odds are against us...like he could lose his job. They fight all the time, but yet he stays with her. I'm so confused. I seriously want to be with him..HELP!