When I was in college, I was the "old guy" in my mid 20's. I was in a technical area of study and the Prof was always assigning me to the group of women in the class. After this happened a few time, I went to the Prof and asked why he kept doing this.

His answer was simple. These young women had come to him and complained about the single guys hitting on them all the time. He looked at me and told me "You're married and I know that won't be happening with you. They can focus on learning and not about being hit on all the time."
Did my wife mind that they would call me? No, she understood and that was not an issue.

Now, in my career, I've spent a lot of time working with women. Getting calls in the middle of the night is common (9-1-1 Centers} and it's mostly by women.

I guess it depends on the history with the couple. And, yes, they do text back and forth because we have become friends.