This man grabbed, intimidated, shoved, held and threatened to punch you, there is never any excuse for that, ever, no justification. Yes you hit him, but I'm sure everyone here will agree that was self defence while you were being dragged across the room. There were 3 incidents, 3!!!!!!!! over an extended period which escalated in the level of violence, all this didn't just happen within a 5 minute window of anger (even if it had there would still be no justification). This man is an abuser, he's just been playing the nice guy up until now. Do you think they all act like a shit from day one? NO, they lure women in by acting like prince charming and 99% of the time the violence doesn't start until after they have moved in, sometimes they can hold onto thier tempers for a year or more, but the halo always slips and by then the woman feels trapped, they groom you mentally and emotionally before the violence starts. They are always so sorry afterwards, then slip the 'BUT' onto the end and twist it to make thier behaviour seem less unreasonable or your fault. If someone is truely sorry they don't add an excuse after they apologise. Some cry thier hearts out, get on thier knees, beg forgiveness, promise it won't ever happen again... But it usually always does.
Honestly, many of us have seen this same sequence of events over and over... Unfortunately I was raised in a home with DV and out of all my female friends and relatives I would say 80% of them have been in an abusive relationship at some point. Absolutely horrifying.
It's almost the exact same story over and over, men like this almost follow a script... You get together, he's the nicest most amazing guy, treats you like a princess, adores you... You move in together, if you have kids, he's wonderful with them, you feel like he's the best thing sliced bread taking on a single mum and kids... Usually it starts with sulking, the odd sarky comment, huffs when he doesn't get his own way, you feel driven to please him, after all he treats you so well... Then one day a switch flips, you have rows, he makes you feel at fault, then more rows, sometimes it starts with throwing/breaking things in temper or punching walls/doors, other times it goes straight into shoving, intimidation, grabbing, pulling, pushing and then escalates from there. What you know of him up to now is a mask, a thin mask that hides a very volatile person.
Has he spoken of his ex's? Does he say they were crazy, psycho, they used him, they broke his heart, that all the problems in the relationship were thier fault? I'd bet he doesn't have many nice things to say about them?
This is the beginning of a cycle and the fact that you are making excuses for him and after telling what has happened you have started trying to show that he's 'normally a nice guy', shows that he has you right where he wants you. You are defending his disgusting behaviour! Step back and imagine your best friend or your sister telling you exactly what you have said here, what would you say? Would you say 'Awww but he's such a nice guy usually' or would you be worried for her future safety?
You have only lived together for 6 months! You should still be in the honeymoon period, having blazing rows let alone it getting physical is not normal.
Honestly, in your position I would throw him out and keep him as far away from me and my kids as possible. This is your chance to see the warning signals and get away :(
Out of the many occasions when women close to me have been physically abused by a partner, only one never had a reccurence after the first couple of times he hit her, but her partner was still a mental and emotional abuser after that which is just as bad :(
You should never ever have to be scared of your partner.