Rejection help

So I was having a going with this guy, then it turned into emotions for me and unfortunately he didn't feel the same. He ended things between us and now he flaunts his new gf in front of me. I'd do the obvious and just avoid them but we live in the same house :/ (it's not incest, bc we're not related at all by anything, we just live together)

Anyways I'll be moving out soon as soon as I get myself together financially. But when I see them together I can't help but to feel a little hurt. How do I deal with rejection?