Is it weird that a married man doesn't mention his wife at all in conversation?

I met a man a couple of years ago and became fast friends with him. I feel that there's a connection between us, definitely great chemistry. I would never make a move on him considering he's married and to be clear he's never once tried to cross the line either. We just enjoy each other's company I guess. He mentioned his wife once way at the beginning, but never since then. I've also never met her, not that I want to or feel entitled to mind you. Would you consider this to be weird behavior?
Is it weird that a married man doesn't mention his wife at all in conversation?
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