I agree with Prodigal. You sound like a person who is lovely. You have done all you can do for your mother and Id keep well away from your ex. Yes is your stuff worth it - or can you get the police to go with you to claim it.
Dont worry about what they think about you because from what I can tell they already have told you. They have used and abused you and taken you for granted.
Hold your head high, claim respect and let them work their own problems out. If your mum gets in a too bad a state, she will get help. It was just easier for her to have you do it because it would have been too embarrassing for strangers to see her filth.
And If any bloke hit me, it would be the last time he saw his fist.