<human>: Give me the gist of the text in a nutshell

I've been dating my gf for 2 years been living together since last August, and this girl is this center of my universe. She loves me back but it's never quite been in the same way, not less just different. 6 or so months ago she met this guy at work and came home feeling guilty for enjoying that he was flirting with her, it didn't even phase me I've never been the jealous type, until recently.

 So fast forward to a month ago she's at school working, I didn't know he was with her, and doesn't come home until 3am. When she gets home she says she has something difficult to say and tells me she likes this guy in a romantic way. It breaks my heart, but I tell her I understand, we were having a bit of a rough patch because of me losing my job. This is where the trouble starts, my gf tells me one day that her and dude had a heart to heart while I'm at my new shitty minimum wage gig and tells me she's decided that she wants to be with me, but wants to go on one date with the guy to figure out if it was him she liked or just the novelty of a new man. Reluctantly I agree, warning her that I'm not Ok with it and that it will make me very jealous. She tells me she can handle that and assures me she can be the understanding one in that situation. After the date I'm devastated, she comes home and I say all the mean and hurtful things that come into my head, she just smiles and tells me she loves me. My problem is now nothing has changed I don't want her to lose her friend but every time I know she's with him I feel furious. I feel like I compromised so much and gained nothing. Did I make a huge mistake?
<bot>: Told my gf is was ok to go on a date with another man now I've got the green eyed monster, help me