She actually said she is “desperate”? That sounds strange. People don’t usually talk like this about themselves. The whole story is strange. My husband only has eyes on me and I am not a jealous person. But if he just got up and left to female coworkers house because she is supposedly desperate, it would not work out for me. Maybe if you are just casually dating, it’s no big deal but still weird.

As unaluna pointed out he is possibly cheating. Maybe not. But he lacks boundaries

Is this the same guy who requested space from you because you just too dependent on him and want too much of him. At the same time he isn’t bothered by the fact that coworker is desperate? So his girlfriend being desperate bothers him but he isn’t bothered by coworker being desperate. He doesn’t want space from a coworker? This guy has some nerves!