The two statements about the more expensive the wedding the greater the chance of divorce and that the larger the ceremony you have the less likely you are to end up divorced seem mutually exclusive to me.
How expensive? Many churches offer an essentially free venue to members. $4/ head for a taco man, get over feeling like you need to get everyone drunk, and all you have left are fixed costs. Our 225-person wedding set us and some family members back in the neighborhood of $8-9k. And we splurged on some things, in our opinion. $4k is not unreasonable.