Boy trouble

So there's this guy I've been talking to for about 3 months well we have hung out a lot and I really like him he's so sweet. But his ex gf and him dated for about 2 years well about two weeks out of the blue he stopped talking to me because him and his ex started talking again but then they stopped well he texted me with a heart felt apology so I accepted his apology well he did it again and he's not talking to me. I really like this guy and he likes me too. He just can't make up his mind. What should I do?