In love with my best friend....whose married

I'm in love with my best friend of 10 years but she's married. We see each other at least twice a week and go out on a regular basis. After lunch today I told her that i was still in love with her after all these years and she looked and me for a moment and started playing with hair and said she was surprised that I still did. Her marriage is..unstable at best. She's brought up leaving him on several times, to me and a few of her friends. They fight constany and dirty, she would rather work late than go home often or stay at her mom's house when he's off. The sex is almost nonexistent. Once every 3-6 months. She's been with him on and off for over 10 years and it's always ended poorly.. She even told me once she wished she could die in her sleep one night instead of being married to him. I've told her in the past that and even recently that she needs to leave him becaise he won't "do better". Thats just what he is. I told her they'd be married for about five years when they got together and her response was "Ughh". It's gotten to the point if she says something about him I'll just say "You know what you need to do" and her respone is "I know". At this point we go out more than they do. There is no sex or kissing between us. Some perhaps inappropriate contact between us. Back rubbing, and what not. And we keep it above the waist. I just want to get some opinions about this.