<human>: On mobile so apologies and this is a throw away. 

Background: I met my SO 4 years ago and started dating two weeks after we met. We are coworkers and have to keep our relationship hush hush. We have a pretty unhealthy relationship. He's abusive. Physically, mentally, and emotionally destroying me whenever he sees fit. I've tried leaving him multiple times but I always fall for his sweet talk and go back to him. We don't live together. We have no children together. I could leave by job at any time. 

Current: He's going through a period now where he's disappeared. He's gone NC all week. I have no idea where he is or what he's doing. He took vacation from work but didn't tell anyone, including me, where he is going. I'm at a total loss. 

The biggest issue with leaving him for me is, every time he's like "OK, I'll let you go" I get close to a panic attack where my heart races, I get nauseous, sweaty, and feel like I'm going to pass out so I never end up actually pulling the trigger on actually breaking up. I have no idea how to get out of this. 

He's awful, I'm unhappy, this relationship isn't going where I want it to, and Idk how much longer I can mentally deal with all of it before I have a meltdown. I'm so scared of being alone forever if I leave. I have no friends because he's isolated me. 

My real question is, how do I get over that panic attack feeling so i can leave?

Could you distill the essence of the text into 1-3 sentences?
<bot>: Idk how to leave my SO who may have already left me because he went NC since last Sunday. Help?!?