Thank you very much everyone, I don't think any words would be good enough to express how much I appreciate your support and encouragements.
Life carries on and work is absolutely crazy so I'm looking forward a break soon. I don't know how to explain it but I know I have done the right thing about filing because if I happen to meet someone I wouldn't want that person to deal with it, but at times I feel sad about it all. I have seen my shortcomings in my relationship although deep down at times I'd have like ex to realise his part and work together as a team. I know I feel sad because I'm tired and when it's the case I feeel down and I cry for anything. This shall pass too.
I'm proud of myself and in a way how ex has very recently started to interact with me. Ex has a tendency to do things last minute but this time he gave me notice to swap weekend. Also he is keeping me more up to date with the kids, so I guess he has realised that I have boundaries and that if I have enough notice I would be more than happy to help him out.
So now coming back on swapping weekend, I had planned something but was able to change it. What I'm proud is that I would have gone ballistic that he wanted to swap weekend when he has his kids whereas has no problem to cancel his activities for OW. Most probably I would have written a nasty/ truth darts to him but I didn't as for the first time I didn't see the point of doing it. It would have served me no purpose, I don't want to keep tabs with ex. I don't want to want revenge anymore, maybe OW is going to bring the best out of him.I just want to be happy and still live by my values.
I can't undo the past, I only wish I had learned more about relationship to make it work. The positive side is that I'm now better equipped.