ex help!

So my ex texted me after 2 years of not talking saying that he was sorry for everything he did and that he just wanted to see me because he misses me and wants to "keep up" and be friends. He also  said that he has been dreaming and thinking about me, I really don't know what this means because he has been with his girlfriend for like a year and a half and he tells me that she doesn't mind if I see him. Should I even bother seeing him? I told him I would let him know lol. I don't know what to do...???