I think my answer to that question would be a simple one. "I don't know...you would have to ask him."There are many forms of love. If you enjoy what you have with him, then enjoy it.
It's probably just the bitter old lady in me, but I would ask these people why they think it is any of their business. This to me is such a monumentally rude question it really makes "Why don't you two have children yet?" seem straight out of Miss Manners.