Asexual friend

Je

A friend recently told me he is asexual, or at least somewhat on the spectrum. He hasn’t sexually been with a woman in many years, and hasn’t felt romantic attraction in even longer. Well, it caught me off guard since I had a little sexual interest in him, but smiled- because we are just friends. I’m a highly sexual person and keep beating myself up about possible rude things I may have joked about in the past. I want to be a good friend, since this is a new friendship. Any advice?