My husband is bi-polar.
I don't see anything in your post that is a red flag other than 3 therapists have mentioned it - that would make me sit up and pay attention. It wouldn't make me label him as such. Moody people are often labeled bi-polar - depressed people are often labeled clinically depressed when they are in fact BP II.
There are 3 kinds by the way - BPI, BPII and cyclothemia. I'm sorry I would have to have some more information on why you (or they) think he may be. I am fine with open discussion and questions about what to look for.