This woman is a pathetic mess of jealousy and anger. How to deal with her?

I'm 21, and I work at a coffee shop with a seriously overweight, very unattractive woman of about 30 who consistently tells the rest of us stories of her blue and how much she hates men. Honestly, I really hate her type. It's like, either swallow a bullet or put a smile on your face! Your miserably mug is exhausting to have at work. We all have problems but some of us are man enough to buck up and deal with it. Anyways, I started dating a guy from work, and when she found out, she started making snide remarks under her breathe and going as far as to tell our boss that we shouldn't be working together (even do we work FINE together!) She's being so petty and juvenile (honestly, is it any surprise that men can't stand her?!) How should I deal with her if it seems like our bosses may be more apt to believe her over us? We both enjoy our jobs and the people we work with. To quit would just be unfair.