new guy or old guy?

Okay so I've gotten myself into a situation.
I have a boyfriend of 5 months. I really care about him. He's sweet and loves me. But we fight a lot, over his persistent drug use and his immaturity. He's terrible at communicating and picks smoking with his friends over me. We don't have a lot in common, and I honestly don't see myself marrying him unless he changes. The spark in the sex just isn't there anymore, but I still care about him.
I met this new guy at a party this weekend. He's really attractive and I had an instant attraction. We really vibed in person, and we have a lot in common. We've been texting and he's flirting with me and I REALLY wanna flirt back.
I'm a freshman in college, and I don't know if I should stay with my boyfriend and try and work things out, or pursue the new guy. I know I'm young and I just don't wanna miss out on someone special. 
help a girl out guys 😩