<human>: Can you succinctly summarize the text in 1-3 sentences?

My longtime friend was dumped by his girlfriend several months ago. He doesn't have many friends, mostly due to his hostile attitude and severe video game addiction. I have known him for about 20 years and he has never really wronged me in any personal way. I have long been attracted to his ex, even before they dated, and last night we confessed our feelings for each other, kissed, use your imagination etc. I knew he was a shitty boyfriend, but the things she told me make me cringe. He had been jobless for well over a year by the time of their breakup, but she revealed to me that he quit the same month that she received a large sum of money for a settlement. He continue to live off of her and did not actively look for work, instead playing video games all the time. During their breakup, he also threatened to stab her next boyfriend (uh-oh).
Jump forward a few months. I've still been hanging out with friend. He has basically begged me not to hook up with his ex. I told him he had nothing to worry about. That was until last night, went after a few drinks at the bars with friends, we kissed. It seems like we started falling for each other immediately. I hadn't felt love like this for years.

We discussed how complicated it would be to date due to my friends aggressive, irrational behavior. If he found out, I could actually be in danger. Alternatively, he might also hurt himself. She told me she can't be with me, cried, and left before dawn.

I spent today an emotional mess. I feel shitty for doing this behind my friends back - but on the other hand, I don't know if I really want to count him as a friend. And I honestly haven't felt an attraction to anyone like this for years. Is there something I can do to make this work? Or should I accept that we just simply can't be together?
<bot>: I want to be with a girl who dumped a shitty "friend" of mine. He might kill me if I do, so she says we can't date, even though we've fallen for each other.