I'd go with something like this. The 2nd is a bit too casual. Include your last names in this one. An alternative to "request your presence at their wedding" would be "invite you to share in the happiness of their wedding day".
If this is the actual invitation, then you need to list the name and address of the location at which you will be married as well as RSVP info (where to send replies to say you are attending or not). If you are going to do that through written invites, then just list the date here.