So stop stressing, cool down your printed wedding invitations aren’t ruined. There are a few options and I recommend which ever one works for you. Get a little bit of ribbon and do some tests on the following solutions. Depending on the type and width of the ribbon it may change! 

Things to stop your wedding invitation ribbons from fraying:

Nail polish: Usually one of the better methods, just dab a little on you may be able to see it if you go to heavy.

Hairspray: Works also but can change the overall color of the ribbon

Wax: Also works can get messy

Burning: A slightly more risk one but slightly burning the edge can stop fraying

Fray stopper: available at sowing shops, made to stop fraying!