Everybody — those with and without ADHD — has these moments from time to time, even during highly stimulating activities like sex. I strongly encourage you to stay calm about it and not read anything into it about your husband or your relationship. Just as important, don’t let your husband read anything into it about you.
When you catch your mind wandering, bring it back to what is happening in the moment. Getting caught up in why you got distracted, or what that means, could distract you even more. If you find that you are more likely to get distracted during certain activities, it may be time to change things up or add some variety to better hold your interest, especially if it feels like your sex life is in a rut. If you take a stimulant for ADHD, you may find that your attention is better during sex while you are getting coverage. If possible, schedule your intimate moments when your medication isn’t wearing off.