am I just a rebound or is it serious? 😕

I started talking to a guy 2 weeks after his gf broke up with him. After 2 weeks of talking me he got back with his ex. He messaged me once a week saying how much he misses me and how the relationship with his ex just isn't the same. Couple weeks later he messaged me and was saying how much he missed me and that his confused because he cares about his gf and their history but really wants to try things with me. That night he broke up with his ex and we are now taking it slow.