bfather not interested after 1st reunion

When I first got the call from the agency that Jordan wanted to reunite, the first person I called was my ex-husband(the bfather) We were 18 when Jordan was placed, and mostly out of spite over parents telling us what to do, got married and had another son together just 17 months later. We split up a year after that. We have remained on good terms. My ex has been involved in my 2nd son's life on a fairly regular bases. Sometimes more than others. My question is, Now that first son has initiated reunion my ex is not as excited as I'd hoped. At first he seemed stunned and was 1 1/2 hours early to our house for first reunion. After that he didn't seem to have much interest. He lives in a neighboring state and the boys took a trip together to visit him. He treated Jordan has if he was one of our son's friends and not his own. He told me this and Jordan felt it. Even our 2nd son felt it. He didn't take one picture the entire visit. He told me that he is suspicious of why Jordan wanted to reunite. He thinks he wants something from us. He also thinks that loving and accepting Jordan is somehow disrespectful to 2nd son. I have had many long talks with 2nd son about his new big brother and have even taken him to a couselor a couple times to see if there were issues he was afraid to discuss with me. He actually is very happy to have a brother. Until now he was an only child. Niether me or ex has had any other children. I have a hard time understanding his kind of logic. My ex is an adoptee who never got along with aparents and was the blacksheep of the family. (3 sibs all adopted) He never talked about his feelings on being adopted much and never had an interest in searching for bparents. The only reason he gave was that "they didn't want me then, why should I want to meet them now." You'd think after placing his own child that he'd have more of an open mind about why he was relinquished. His family was very good to him. He fell in with the wrong crowd and got himself in a lot of trouble when he was young. OK I'm getting way off the subject. Has anybody else felt that they do not want to reunite or know why another bparent does not want to reunite?