my boyfriend is abusive

please help me. i dont know what to do. my boyfriend has hit me and grabbed me by throat a few times before and yesterday it was the same, he hit me an pulled my hair i didnt do anything back and a few hours later he apologised and said he knows hes a horrible person, i told him i was thinking of splitting up with him because i cant take this anymore and now today he lunged at me so i swung for him n caught his face but it wasnt hard at all and i barely touched him and he went mental, started grabbing me as usual and lunging at me and im sick of it, he always threatens to leave and i always stop him, he threatened to leave again today and i didnt stop him but he hasnt gone, i want him to go and it upsets me that its got to this. im absolutely sick of him. were meant to be going on holiday on tues and i dont even want him to come, its going to be a horrible time but i dont want to go on my own and its too late to ask a friend to come with me. he was going mental at me for hitting him when he lunged at me and i did it in self defence but he was shouting at me saying i shouldnt of done anything cuz he lunged at me!!! so basically is he saying i should just let him lunge at me and not defend myself and hope he can be strong enough himself to no hit me? i think hes mental, please please help me and give me your views, am i in the wrong or what cuz im really confused.
thank you.