Dignity is the key here.
Get your things back - being very nice to everyone to ensure there is no suspicion.
Get your locks changed.
Ignore any contact with them, except through your solicitors.
Easier said than done I know - but there are relationship and legal issues here.
The legal issues can be rsolved through mutual legal advicec, and you should refuse to discuss the issues with either of them by phone, letter, or conversation.
The relationship issues need you to walk away with your head held high. Drop them both, and simply refuse to speak to them personally or by phone, e-mail, letter, anything.
This silence may be seriously hard to keep up, but when you look back you will be so glad you did it that way. It means no-one can ever say anything nasty about you, and you don;t tear yourself up in futile rows that simply don't go anywhere, and benefit no-one.
Shoes and handbag.
Locks changed.
Silence.
Do it - I speak from experience - it works.