Characters in-universe have hinted at it. http://www.bleedingcool.com/2015/04/21/ ... ed-as-gay/
There's more out there. Emma also apparently confronted him about it once but I don't remember that.
But hey, guess what? Past Bobby grows up to be an ice wizard. You know who else was a gay wizard? Dumbledore and he was ducking awesome.
But nah, She specifically says Present Bobby isn't gay, which means...what? He went through a phase and turned out straight while the younger, past self turned out gay? Doesn't make sense to me.