ive been in a relationship with a girl for 3 years now. I am her first boyfriend, and first partner, and things had been going along great until about 6-8 months ago the relationship began to lose its luster and it started to feel like we were just friends rather than dating. We eventually stopped having sex for a while because we were always tired and just wanted to go to sleep when we saw eachother. meanwhile a different girl has come into my life that has offered much that has started to lack in my relationship currently making me think its time to end it. The problem is I feel so ready to break it off with my girlfriend but when I actually try to I cant help but remember the good times and I run back to her hoping that things will magically be better. What should I do?