Help! I may have done the most stupidest thing to my best mate, because of his infuriating girlfriend. WHAT SHOULD I DO?

Anonymous
My roommate is my best friend, however he recently found a girl who he thinks is the ''one'' and spends countless nights at her house or wherever she lives, he texts me and calls me during the day yet never comes home or spends time with me, but awhile ago he invited me and his girlfriend to a restaurant, and it was the first time i had met her, i had my fingers crossed she was not going to be a total bastard because when i saw her she looked like she worked at a bar, and was complaining about how the food was not cooked properly and was a total racket she pissed everyone off at the place, yet i tried keeping my cool until she somehow took the liberty of moving onto my best mates looks, saying he should go to a salon or look more like her ''Ex boyfriend'' which was really pushing my buttons, and then she took it to his family... about his mom, i don't think she knows his moms in heaven, or maybe she did but she pointed out the fact that his mom never taught him how to ''look good'' or how his parents might have had a really bad taste. I was not listening more of concentrating on not bursting out but well i have a problem with bottling up my anger especially when someone insults my best mate, so i got up and slapped her and left the restaurant i took my car and left, i was really pissed really really, i on earth could he keep up with her? my best friend texted me saying he doesn't want to leave her i haven't replied any messages at all, just now his girlfriend texted me after i had slapped her a death threat? nope, i wish, she said i ''BETTER NOT TOUCH HER BOYFRIEND'' i wonder what she meant, lord im about to die... WHAT SHOULD I DO? HE TOLD ME THAT HE WANTS TO STAY WITH HER"?
Help! I may have done the most stupidest thing to my best mate, because of his infuriating girlfriend. WHAT SHOULD I DO?
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