Spinoff on invitation wording

My FH parents are divorced and his mother remarried but we didn't put his step dad's name on the invitation, we only put his real parents names. Here's what it will look like.....

Mr. and Mrs.------
request the honor of your presence at the marriage of their daughter
Jennifer
to
FH name
son of
Mrs.----- (his mom)
Mr.--------(his dad)

Is this wrong??? FH likes it and didn't even question it b/c he feels his parents are both represented but I feel bad..it didn't even cross my mind until now that his step dad was left off!