Told bf I want to separate and he needs to stay somewhere else...

So my bf and I got in a big fight , I told him I need space. not that we are breaking up but we need time to think and figure out what we want. and also make major changes. the next day he packs all his stuff and goes to this friends house "a girl he knew since high school" and she offers him a place to stay , spare bedroom. We then that night talk about arrangements I thought he would stay with his grandma but he mentions how this girl offered him a room. I dont really like this girl personally she is a hoe and gets with so many men its nasty. He says he knows this about her and that's why he never pursued her and they remained friends. but I feel weird that within 1 day he is staying there no questions asked, and now he left to go have dinner there cause she is cooking. should I feel some sort of way? I really dont want him here but dont want to take him back in just because I'm jealous or trying to avoid him hooking up with her. should i let him be, we are both under the impression we want to be together but we need to work out some issues on our own. we have 2 kids ...