<human>: Can you give me a shortened version of the text?

Without going into too many details, about three years ago, the person in question stole money from me, sexually assaulted my girlfriend, and when I cut ties with him, he got me fired from my job by calling in and disclosing a marijuana arrest from when I was a minor. 

Tonight is a close mutual friend's going away party and I would be truly remiss to skip it just on account of this asshole. But I'm very uncomfortable with seeing him in person and am not sure how to act. I've seen him once in the last 3 years at another event and he regularly would walk up to whoever I was talking to, knowing I would walk away. I don't want to repeat that tonight. 

Any advice on handling tonight? 

Note: the sexual assault was reported, which is one of the reasons he felt he had to "get back" at me by getting me fired.
<bot>: Asshole ruined my life a few years ago, now I have to see him at a party tonight. How do I deal with my emotions and him probably trying to start shit with me?