I guess I'm lucky in that I've never had any odd behavior anything like that. Of course, my dogs tend to be a little odd as it is, so maybe I've never noticed? ;)
Personally, I'm of the 'I'm glad they spayed.' camp. Looking at the situation, a lot worse things could've happened to the dog beyond getting picked up and spayed.
Most of my family members I know I can trust to watch my dogs, same with some close friends. Though, really, I just take my dogs everywhere so it's usually a non-issue.
That's why I often try not to do anything too much that I enjoy, for the fear that I burn myself out on it. I've done it in the past, and it's just no fun. So you're not alone. :)
My two little Yorkies seem to love to go to our local dog park. Typically, there's not many people there, so we like to go and they love the smells and the squirrels. Since they're so small I prefer to harness them, even though it's an off-leash dog park.
Haven't taken them to a beach yet...