I'm not 100% sure. Scandinavia names remain somewhat common around here but I'm from the East Coast and am unfamiliar with them.I doubt her husband would go along with Trygve, her original pick was Theodore, then a close friend used it.
I'm guessing it's a bit like Trigger? If that's the case, I don't really like it then. It would remind me too much of guns! I like Theodore a lot, especially with the nickname Teddy on a young child.