Love Sucks

So everyone has troubles with Love in some point of their lives. Well, that would be two of my friends now. Since I want to protect their privacy, I'll use code names. Well, my friend Shay and my friend Cody started going out last year. Man were they a cute couple. Well.. as the year almost went by, Cody started acting a bit different. This didn't bother the rest of us a bit since everyone tends to change as we enter high school. The only thing though, Shay was starting to get scared because his changes were a bit more violent and he started to get jealous of other boys talking to her. I thought they had just hit a rough spot, and if they didn't fret about it, it would go away. Shay just jumped to conclusions and ended the relationship.
Well, it was all fine and dandy till they figured things out and got back together. Even though I frowned upon it, I still tried to support them like a good friend. Then Cody's attitude became a bit worse and Shay ended it again. Time passed by and Shay moved on and started dating another guy. Cody is taking things really hard and can't seem to let go, no matter what he would try. They're trying to be friends, but every time they talk to each other they seem to get into a fight or they finish talking and realize they still have feelings for each other.
I want to help both of them, but I'm bum out of ideas. Is leaving them alone the best option for now?