So far as I know, you have all the same rights to the house that she does.
You could go there, break into a back window, and then change all the locks if that's what she has done.
I've been through this before.
That said, if you did that, it's really likely she'd call the police, and you could potentially find yourself in trouble. Not for breaking into your own house, but she could easily say she's afraid of you, file a restraining order or whatever.
You should likely speak to a lawyer soon. Also, what's the story on the bank accounts, but bill paying, etc?
You don't to answer me, but she's probably moved money out of any joint accounts at this point.
You need to talk to a lawyer fast in my opinion.
If I were you, my soon to be ex would have already been served divorce papers and I'd be going about whatever my lawyer told me I could do to protect my rights in all of this.