Only if you have advice on how I'm supposed to tell mine about dating a "lowly shapeshifter". ;)
In all seriousness, I would just sit down and tell him exactly what's going on. (Minus the gory details) Just lay it all out and explain what you want and who you want, but that his opinion means a lot to you too so you want to be open with him. He doesn't strike me as the type that will flip out if you're reasonable about it.