My Grace (GSD, spayed, 9 yo) has recurring health issues, namely EPI and ongoing vaginal fold irritation, with some sebaceous cysts thrown in for good measure. Luckily, she is a treasure temperament-wise

In comes Vigo, my intact 10 mo male, who just LOVES Grace. She is the only dog he will act "studdy" around even though we have two other female dogs and he is in contact with lots of others. We're talking "nose up the butt, trying to mount, sniff/chatter/drool/mark her urine" boy stuff. I realize that all of that is training issues and we are working hard and making great progress.

Part of this definitely originates with her fold problems and the smell, but aside from daily cleaning and applying ointment there is not much I can do.

But I am wondering if she has something more going on...thinking urine pH?

So I guess I have two questions:

Did anyone ever have a male that did this behavior towards only ONE female?

If so, did the female have any diagnosed health issues (specifically to do with urine, etc)?

Also, Vigo is my first male dog ever, so all this is new to me...but he is steadily improving which I definitely consider to be a great thing considering he is maturing at the same time and I thought it would get worse before it got better.