Anne makes a good point. If it's not an immediate concern, just something you're idly pondering, then I would bring it up as rhetorical/hypothetical. Let him know right off that there's no pressure to agree or feel a certain way about it, you're just exploring concepts.
“As I am sure any cat owner will be able to tell you,
someone else putting you in a box is entirely different
from getting into a box yourself.” —bisexualbaker