Dear Sandi,
I think it's terrific that you're sharing this and, from my own experience, your feelings are very understandable. You and your husband were ten years older, more mature, and wiser than when you married. Hopefully you're both better able to be sensitive and understanding of each other's feelings and talk openly to each other.
Neither you or your husband wanted "this" but you each selected each other, maybe him you because he sensed that you might be accepting and remain loving, and you him because of an indefinable quality that you didn't find in other men.
The most important thing is for both of you to communicate. Easy to say, hard to do, without reacting. It's natural for us to be emotional, threatened, and hurt. I believe this also provides an opportunity for you both to deepen your relationship through building trust of vulnerability, acceptance of each other, and love.
I wish you both the very best,
Emma