Ex girlfriend of 4 years - playing games?

Story goes, have recently split from GF of 4 years, just over a month ago.

Are currently still living together due to owning the house together and i am paying off the mortgage until her bank can pay me out my half of the equity.

We make an agreement to not have people over (friends or otherwise) while we are sorting the house/mortgage/etc just to avoid the potential unneeded drama.

So far, everything fine, reasonably amicable. I keep my girls (and what i do to them) completely seperate from her and the house out of respect and she does the same... (or does she)...

Couple of nights ago I come home from town in the early hours and she makes it a POINT that she made out with someone in town. At first im thinking "what the fuck are you telling me for", then i dismiss it by saying i did also (true story).

Fine, whatever, pass out for the night.

Next day, im packing my shit into boxes preparing for the house move with a mate, and she blatantly invites her friends over AND this guy from last night over and closes off the lounge so they can hang out.

To me this a TOTAL breach of respect and now have none for her at ALL.

My take on this is she is trying to rub in the fact that she has got some new guy on the go. I honestly dont give a FUCK about this guy and what they are doing, but the fact that she invites him over to what still is half my home in an attempt to make me jealous, frustrates me.

Later, she sees this and asks whats wrong. I tell her that what she did was disrespectful and quite frankly, pathetic.

Now, she wants to go to one of our mutual friends' birthday parties (obviously bringing this (or another) dude).

I really can't be bothered trying to play the whole, "lets bring a new girl/boy and pretend to be amicable at a party together" game.

What do you guys think of this situation and thoughts on how to handle?