<human>: Can you give me a shortened version of the text?

So basically I've been seeing my BF unofficially since October, officially since January. Things have been great. We have fun together, we have common interests, we can sit in silence in complete comfort. He's met my family, and his family knows about me (they don't live in the same state), we know each other's friends. I feel myself falling for him, and I'm pretty sure he's feeling the same. However, I've been kinda worrying about possibly being a rebound. His ex and him were together about 5 years. They didn't live in the same state the past 2-3, and I'm not sure they were actually together for that time either, more like kinda broken up/kinda not. 

He's been very honest with me about her. They were definitely broken up when we got together for at least 6 months. However, during the beginning of our relationship she would still try and contact him. I know that she's still paying him back a loan, and I don't have a problem with them being in occasional contact, I am on cordial terms with my past ex too. I believe him when he tells me that there is nothing romantic between them anymore, that I make him much happier, and that I have nothing to worry about. 

However, I'm worried about being his next relationship out of such a long term one. I've heard nothing but bad things about "rebound" relationships, and even if he doesn't view me as a rebound, that I am. What are some warning signs I should look for? Am I bound to be heartbroken?
<bot>: Boyfriend got out of long-term relationship a few months before me and even though we're getting along great I'm scared I might be a rebound.