Most Helpful Guy
The longer you go on, the more hurt you both are going to be when it does end. You will find you have wasted 6 months, 16 months, 6 years. The only way this can ever work is for both parties to agree to put the relationship, the kids, the family first before there is any consideration of religion.
Most Helpful Girl
Just end it now, why continue in a relationship with an inevitable end like that? It'll just end up hurting more to stay like that. Let him know you want to remain friends but you both know the relationship won't go very far.