That guy will always have boring relationships with girls that are your age and look like you. The thing is. You are a type that feels that he is not enough. And maybe this other new girl that he is with will leave him too if she is like you (type). As far as him having your stuff laying around, does not mean anything, he might not even be aware of it or maybe thinks that you might return for them. In either case if these are valubles, come back for them, if they are clothes or shoes and etc., dont. I have had bad relationships where I left and never came back for my stuff cause I was badly hurt emotionally. Start doing cool stuff for yourself like, go hiking or drive out to see nature, go travel, go to the mall and walk around and check out new cool items, buy some sweet shake or coffie, eat an expensive piece of chocolate. Love yourself, dont think about bad thing that happaned to you, otherwise you will cry and your chest cavity will hurt like hell.