I'm sorry for your loss
I was also in a V, and my bf broke up with me about a week ago.
and i live with him
he's now mono with the girl who was his secondary.
Some people just can't take it, some people are just not Poly. IT hurts like hell, but you will get through it and you will find someone who fits into your life in a more productive way.
Meanwhile, busy yourself, it doesnt matter with what, but get involved in something.