Here are a few ideas for casual wedding invitation wording hosted by a divorced parent:

Rick R. Towers
invites you to the wedding of his daughter
Lorie Lynn Smith
to
Julius Anderson
Saturday, May 17, 2012
at 4:30 in the afternoon

Rick R. Towers
invites you to share in his joy at the marriage of his daughter
Lorie Lynn Smith
to
Julius Anderson
Saturday, May 17, 2012
at 4:30 in the afternoon

Rick R. Towers
invites you to share and celebrate at the marriage of his daughter
Lorie Lynn Smith
to
Julius Anderson
Saturday, May 17, 2012
at 4:30 in the afternoon

If the bride's last name is the same as the parent's, there is no need to list it.