<human>: I'm to the point I want to cut it off with my girlfriend. We've been dating since early high school, but she's changed and I don't think we're compatible anymore. She was my first and only girlfriend thus far. I've tried breaking it off with her in the past (twice), but each time she's been able to sway me back some how. I need to be done. The more I think about it, the more daunting this becomes to me. She's become so entrenched in my life that I'm now close friends with her family/extended family, father, and most importantly her brother, whom I've had a pretty great friendship over the past 2-3 years. I've been contemplating breaking it off with her for the past 4-5 months, and I think I've reached the breaking point. The expectations of her family is that we would be engaged within the next 2 years, but that cannot happen. My family expects the same thing, but I can handle them. Also, I'm currently one of two friends she has. Her best friend she hardly speaks with at all, her mom is out of the picture, she doesn't have a good relationship with her brother, and she can't be honest with her dad (he's really judgmental and critical of everything of her), so I'm pretty much it for any and all support emotionally. She's incredibly introverted, so new friends isn't really something she actively wants. I feel like I'm dumping a huge load of shit on her, but there hasn't been a convenient time in the past few months to do this and now I think I'm just making up excuses for staying with her.  

It's not that I don't care about her and what happens to her. Shit, I'm probably going to love her long after we break up. I just am no longer happy and haven't been for awhile.  

How do I get myself motivated enough to break it off?

Could you distill the essence of the text into 1-3 sentences?
<bot>: I've never broken up with a girl and this is going to be absolutely daunting for me because of how long we've been together. I have no idea what I am doing.