SUBREDDIT: r/relationships
TITLE: Me [26 M] with my girlfriend [25F] of 2 years, not feeling "it" anymore
POST: Hi all. I've been with my girlfriend for two years. It's my first major relationship out of high school/college. We have an apartment together with about 9 months left on the lease and we have a dog.

I've been relatively happy and whatnot but recently I've started feeling fairly indifferent towards the relationship. I feel like we don't really have a lot to talk about and she doesn't really want interactive conversations- she just wants me to listen.

I've been playing rec league softball with some friends from college and have become friends with a girl there that strikes me as so much more interesting and someone that I am much more excited about spending time with than my girlfriend. We haven't hung out outside of softball but I spend a lot of time thinking about her. I don't really want to have a relationship with this girl it just made me realize how uninterested I am in my current relationship.

I know my girlfriend will want to get married at some point in her life. I don't. I don't foresee this relationship lasting more than a year longer or so. I guess this makes me seem like kind of a bad person but I'm not sure how to approach the situation.
TL;DR: 
How do you know if you should break up with someone with no external factors (cheating, job moving, abuse, etc.)