Happy vs. Hostile Environment: How To Deal With Having Your Divorced Parents At Your Wedding - Page 7
The solution
If your parents divorced because one of them was unfaithful, it’s not unreasonable to request that the mistress/lover does not attend the wedding. If your parent has been with that person now for a long time and is even happily married to him/her, you may need to ask the parent who was cheated on to do you a solid and let them come to the wedding.