<human>: Give me a shortened version of the text

OK so this is my first post on reddit and I'll try to keep it simple. I've been dating my SO for a year and 9 months now and for the last few months I've been having strong thoughts about breaking up with her, although I still love her very much. She's basically perfect and sometimes I'm not sure why I'd want to break up with her. She has mild idiosyncrasies but everyone does, although Im finding them more annoying as time goes on. However I can't stop myself having the desire to be single again. A few months back we had an argument (very rare) and she starts crying so I hug her and it goes silent, and I remember in that moment thinking, and wanting, her to break up with me. Just so I wouldn't have to struggle with this. 

There was another incident more recently of another girl flirting with me and being really cold to my girlfriend, which has led to her being largely ostracised from our social group. Yet I can't stop myself from being excited by it and having my heart race every time I get a message from her. I don't flirt back because I couldn't do that to my SO, but each time I really really want to. I've also noticed acting more like a single guy when I'm with m py friends and a hot girl walks past. 

Yet despite all this I can't imagine my life without my SO. She's so kind and sweet and beautiful and even though I currently stand on breaking up to her tomorrow, thinking about it made me cry this evening (not something I do often) which has just made me even more confused. That's why I need some advice, even if I don't get a definitive answer, anything that'll help me figure this out will be massively appreciated. Oh and to make it worse her birthday is next Monday and although I don't want to ruin her birthday I also don't want to spend £100 on something she'll likely throw away if I do it soon after.
<bot>: I love my girlfriend but really want to be single again. I'd never cheat on her so that's not an option, but need some advice! Thanks