<human>: Condense the text into a few key points

Sorry for throwaway account. My girlfriend uses Reddit, although very rarely.

I've [21M] been with my girlfriend [20] for almost 3 years now, and I've been pretty bored with how things are for a while. She's an attractive girl, but I've been bored sexually for a long time. We try new stuff to spice up our sex life every now and then, and we have sex at least 2 times a week. But all I've wanted for the last 2.5 years is to sleep with other girls. I've managed to see past it and stay loyal.

However I recently started a new job and there's a hell of a lot of girls my age and temptation is there. My main worry is that I've become so incredibly infatuated with this 1 girl that I can't stop thinking about her. We have 10 days of work left before she moves to another dept and I won't see her again, and then a month after that she moves back to University anyway. We flirt a bit, although I'm not too sure on her returning the signals as I'm pretty oblivious to them (although 2 days ago she starred into my eyes with her goddamn big beautiful eyes for at least 7 or so seconds with a big mouth-open smile whilst neither of us even said anything). However, she's mentioned an ex-boyfriend and her staying over at his last week and them sharing a bed (but nothing else happened apart from some spooning) because the friend she was meant to be getting a lift with (from a night out) bailed on her. After that happened he has been texting her saying he loves her. She also mentioned them ending on good terms, just he left her because she was at uni.

Is it normal to get this infatuated with people whilst you're in a relationship? The last time a girl plagued my mind for this long was at school (5 years ago). Because even when I fell for my current girlfriend we got together so fast that I can't even remember the sicky feeling you get in your stomach when you like someone this much.
I have no idea what to do. I love my girlfriend, but i've been incredibly bored and fed up for a long time.
<bot>: I love my girlfriend, but bored. There's another girl who will only be around for the next few weeks, but I cannot stop thinking about her.