Common assault charge against ex, what to do?

My partner and I were together around seven months but I decided I had had enough due to his constant mood swings, controlling behaviour and agressive nature at times. I told him I wanted no more and he has harrassed me which the police warned him about after an argument took place at the top of my stairs and he tried to push me down. He was warned to stay away or risk arrest.
However, he hasnt stayed away and turned up last night and tried to cuddle and kiss me etc, neighbours called the police and he was arrested. he has since been charged with common assault as the taking hold of and trying to kiss me was classed as that.

I feel horrendous, I feel like i have landed someone that I love very much in alot of trouble and have effectively ruined his life by making a statement to the police, I cant switch off from it and feel like I need to explain to him. I am frightened he will harm himself as he has threatened suicide in the past.

If I were to write to him and explain would this be seen as interfering in an ongoing case and would I end up in trouble too? I really really dont know what to do and the guilt is making me physically sick.
I know he was wrong to turn up when told not too and to try it on, but I feel it was out of desparation and not a ploy to cause harm, do I have anyway of making the law see it that way or is it out of my hands. Please help someone and advise what to do as I am going stir crazy. Many thanks