How to deal with a break-up you weren't prepared for? Part 3?

I have posted several questions on here in recent weeks, hoping for advise on how to deal with a long term relationship break-up. I have to admit, despite everything I had still be hoping on a small level that my ex would realise his mistake %26amp; we could work things out. However this morning I received a phone call from a friend who had driven past his house on her way from work last night %26amp; to work this morning %26amp; seen a car parked in the driveway, which had been there overnight. She told me because she is my friend %26amp; thought I should know. Maybe this wasn't a good idea but it's done. So I didn't know what to do so decided to call him %26amp; ask if he has been seeing someone else. He replied, rather uncomfortably that yes he was %26amp; that she had spent the night (in our bed). He said he couldn't talk because she was still there but would call me back. 10min later he called. He explained that he met her 2-weeks ago (1-week after we split) %26amp; had acted on it a week later. He feels she isn't someone he can see himself becoming invovled in a relationship with. This upsets me because I never thought he was a one night stand kind of person. We had a loving relationship built on trust %26amp; now I don't recognise this person he has become. What concerns me now is that I feel rather numb %26amp; don't really know how I feel, whether to cry or scream or yell. He told me he was worried about how calm I was %26amp; he wanted me to yell at him but if that's what he wants, I won't do it. I want to be the better person at the end of this because I truly believe after he's had several one night stands, he'll feel terrible %26amp; empty inside. I'd appreciate some advise on how I should be feeling %26amp; dealing with this latest setback?How to deal with a break-up you weren't prepared for? Part 3?
i dont know, that sucks though. maybe ignore him, i dont know i would really tell u to forget about hima nd find another but i know its easier said than done when u really care for soemone. but after this u really need to try to forget about him and move on with ur life. u dont deseve to be with someone who would do that. he will keep doing it espaeacilly if u take him back and he knows he can get away with it. u really need to move on. umm, if not , ignore him, make him suffer, make him pay for what he did, make him do everything for u, and use a condom for sure everytime since u know he is a cheater. i dont know. good luck. im going through what i think will soon be an ending relationship as well. i know hes no good for me but im just so stuck on him, guess it will take time for me to move on. or maybe ill hang in there and try to make it work. relationships hurt, i wouldnt bohter with them if i dint wan tto be in love and dint love the feeling of being in love an dhaving someone love me.