This made me laugh out loud. And I'm the wife.

If it is the only thing on the menu you like as you stated, then have it arrive when the other meals come. However you did say you got a meal as well, so I am confused!
Or, if they eat it all, order another one. Maybe they will offer to share in the cost. You have all night, right?

We went there with another couple and his wife kept urging us to try his bang bang shrimp. If we do share an appetizer, we offer to share the cost

You are right. Your wife is right. Your friends are wrong. get some new ones