Hmm, if they were attacked a total of three times and no one ended up in the hospital, I guess my first question is what kind of encounter was this?
If three people truly want to hurt one, from my little experience it's not too difficult. There is so much to the story we don't know from your description.
How would I handle it? Well truthfully i'd start by not being in a place like this:
a busy downtown street with many bars and clubs.
Sounds flip, but it's true, my guess is there were mistakes made long before the actual physical stuff started, it's probably worth looking at that. Youth + Alcohol + Ego..always a great mix.
We don't have enough information here to know to what kind of "fight" this was, a light punchfest and name calling session requires a different response than something worse surely.
That said, if I felt my wife was really in danger from someone, I would do what was needed, regardless of the sex of the attackers....
Again though, there are so many steps leading up to an encounter like that which should be looked before the physical encounter. Not trying to downplay the seriousness of it..but if this was just a fight with little physical danger, it's a different deal than someone actually attempting serious assault...and it's probably worth figuring that in.