Most Helpful Guy
Honestly I don't think it was a big deal, that he was texting her, but the fact that he was doing it while he was talking with you, when he should have had his full attention on you was rude and should not have been done.
Most Helpful Girl
It wasn't wrong to end the call if it was bothering you. Honestly, I probably would have done the same thing. Its an impulsive thing (to hang up on someone) we can't really help, especially when our emotions are involved. Although, I think we'd see better outcomes to things we do if first consider possible end results our actions might be enabling and then act according to the results we'd like to have (rather than do something impulsively which could result in an outcome we didn't intend). For instance, you hanging up on him really only gave him more of an opportunity to then communicate with Allison, and is most likely why you got the "ok night" response from him.