Have you been ever in your adult life living alone?As it is, I don't like the idea of living on my own, I have this need to have someone at home, and I have the need to sleep in a bed with a woman I am attracted to. That's why being totally single is not something I've considered so far, even if I live in a big city where middle aged single guys are spoilt because of the male/female imbalance.
I am afraid this is going to sound arrogant and maybe it is, because there certainly are some assumptions about "how it's done". But I want to add my voice to the concern of others.
I do understand that you don't like living alone, that you want to come "home" to someone. It is beautiful to have a loving bond and closeness, which is manifested in meeting everyday and sharing the mundane.
But to want someone so badly that you don't consider living alone after the breakup? You seem to be acting out of a place of fear. Probably a fear to meet yourself with your insecurities and depressions, which often happens if you are alone.
I may be totally wrong, projecting, but I can see how the same fear would hold you in a bad marriage for such a long time.
In this case, moving in your gf would be just an outside fix, and kind of rude to her, because you don't act out of love but out of fear and would move in just about any attractive woman. She might rightfully feel pressured after a short time.
It's fine to avoid fears by seeking an outside fix sometimes , especially if it's not just a 'challenge' but 'terror' thing, that you are aware of but don't feel like tackling, and I certainly won't judge you if you do avoid this one. But since maybe you are on the way to realize it now? I think you could have a look at it, take the challenge and transcend it. You will be rewarded by more confidence in yourself.
You seem to be getting on track, and I wish you luck.