So, I spent a year abroad (living with host families) in Europe a few years ago, and most of my fiance's family is still living in his home country in South America.  I would really like to send wedding invitations to family and host families.  However, I don't want them to feel obligated to make a huge trip out here for a wedding, and I don't want them to feel bad when they decline - we just want to share this news with them.  I would like to include a handwritten note about how we wanted to let them know, and that they should not feel obliged to come.  But as you can see, I'm completely floundering on the wording.  Any suggestions?
Thanks a bunch!