Abuse but I'm in love

I have been with the guy for so long now, we have very happy times where we are so in love, but tonight while we were hanging out a girl facetimes him, then proceeds to say how they hungout and get drunk together. Blah blah blah. I confronted him to which his response was grabbing me around the throat while threating to kill me. I was shaking. He then held me until I looked him in the eyes and said I loved him. I told him to go love the girl calling and he got up and walked out and started punching himself in the face. I know you will all just tell me go leave or get out of it, but I stay because of the good times. i don’t wanna focus on the bad. but at this point im scared and need help and friends bc hes isolated me from everyone.

UPDATE:

things were better after the whole issue above until today things got heated again, while we were babysitting kids. he slams the door of the house and breaks all the glass in my attempt to walk outside

the kids huddled up in a corner and started crying in fear of him. after he cleaned it up he came over and grabbed all of us and said he was sorry and he over reacted. the night continued and was fine. until his mother got him and he told her about the argument and she sided with him. which made me angry and i left. she doesn’t even know all of the story, i need go stay away this time, it’s just very hard.