Welcome to this site! *hugs*
From a layman's point of view (not a JW, married an unbaptized publisher), they don't pass around a basket or anything. You sound like a very logical person, and your question is valid. The "hook" as you would think of it is the fact that they get free labor. They have very cheap labor at the publishing HQ since they don't earn a salary there, but are provided with food and shelter. (as far as I understand it, someone correct me if I'm wrong please). The labor of going door to door is free labor since you're not paid for basically advertising this organization.
Don't freak out yet bro. I studied with JW's for a while before I decided that I had learned enough about the beliefs to realize I could never become a full member and expect to be baptized. Take this time to love your wife and give her extra loving attention. Tell her she's beautiful and you're crazy about her.