Be a man, be honest, tell her its not going anywhere and you want out. Why are you hanging out? It's not fair to her or even yourself to carry on with this when you're clearly not committed to making it work.

Stop being a wuss and do the right thing. End it.

Short version: Lots of things dictate that we see each other a lot and spend a lot of our time together.

Basically because she won't accept an actual separation. I tell her I need space, it turns into a fight, then she shows up when I've started to miss her. She'll keep telling me she loves me, and kiss me goodnight but that's it. It doesn't help that we live in the same house, or that her dog has to stay in my apartment because she has bad hips and can't handle the stairs up to my gf's apartment. Oh, and moving out isn't really an option for me either since I'm in the process of buying the house from her.

The reality is the only difference in the way she treats me when we're "together" vs. "separated" is sex.

Clearly, she is in control of the situation. You can maybe not control the dog, the appartment etc., but you can retake control of your own life: be clear that it's over between you, and do not get sucked in to her drama.

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One of the most useful things you will ever learn about body language.

This.

I think I'm especially terrible at "not getting sucked into drama." I think you're right, however.