I go to the dog park a lot with my dog and have noticed that GSD's don't play the same way that other dogs do. They are "mouthy", "nip" at each other (very oral players...is the best way I can describe it). Some people don't take well to that. They think they are being agressive. With Jericho, he will sometimes pick out a dog that is kind of timid and just be a total jerk to the poor thing. For that he get's bitter apple and a "break" from playing. Usually, that is enough to divert his focus away from that dog and back on the one's who enjoy playing with him. I wouldn't muzzle your dog at the park, but maybe if the park is really busy be ready to leave early. I would still try and see if it's going to be a good play day, but be prepared to leave if you have to. I also go to the same dog park every time, just so the crowd is more predictable and will be familiar with how your pup plays. I think it's really important, for Jericho at least, to go and play with the other dogs so he learns how to play respectfully with other dogs.
This is terrible advice. SOrry for the harshness, I'm sick of the excuse and misconception that "it's really important for foofoo to learn how to play with dogs at the dog park." I see you're in Washington...me too (Vancouver area). A few weeks ago a dog was killed at the dog park a few miles from me...killed. Dog parks are one of the worst ideas in the "dog world." imho. You have no idea who the heck is there, what their dog is like, what their obedience is (usually zero reliability), you are basically throwing them all together and hoping for the best outcome. Sure, there are people that have no issues (the best I've heard of are the dog parks that you pay a fee to get into and need a key)....but even then, still seems like something people do to fulfill themselves, lots of weird people, stories, and "advice" can be found in plenty at a dog park. To top it off, your dog has NOT learned how to be with other dogs. So much so that you routinely bring bitter apple spray and give time outs...
So your dog isn't learning anything.
OP, your husband is right to be angry and you are right to be embarrassed. Just take it as a lesson, and move on. Your dog learned right from the get go, I get snapped at when I come in here, and then proceeded to make sure she was the first one to snap next time. You don't need a muzzle, you would really consider muzzling your dog just to take her somewhere where previous incidences occurred in preparation for future incidences?? If you want to do something with your dog, join a club, make it interactive (not just turning her loose with a bunch of unknowns), play with her yourself, go hiking, take car rides...if you believe she simply can't live without contact from other dogs (not a GSD trait, nor will she be missing anything by not), then join classes, makes sure the interactions are purely positive, with older, mature, stable, strong nerved, dogs.