I wonder if Dilemma Girl is using the JW jargon (worldly Christendom girl) because she is somehow convinced that the Watchtower is right.
You're asking about what could be in the guy's mind. I am more interested in knowing what is in your mind.
You know, Dilemma, I was in your shoes (sort of) once. I think I understand what you feel. I surmise you're at the point where you have realized the Watchtower is not good, but are not clear just how bad it is; and are also secretly hoping that the love of your life will eventually see it that way, too, since he has manifested disagreement here and there and has already made it known that he's involved with you. In my experience, the odds are against you. I think he will not be involved with you unless you give in to the Watchtower.
In my opinion, a worldly will not join the Watchtower once s/he knows what it really is. I am afraid that all you would need would be a little pushing to join. The prospect of being with a person you truly love, a person who truly loves you, makes it look like joining is not really a problem. The brothers and sisters are all so nice and you have an open mind. Doe anybody really know what is the true religion? Maybe they are even right. They are actually right here and there...
Then you will feel that this is a problem you can handle. Or it is one you can handle even if it's difficult. Or it is difficult, yes, and very much, but you're not a quitter and you love him and he's so great when he's not in Watchtower mood. And then you have kids who are so proper and look so great in their suits.
Making the decision not to join is heartbreaking because you realize that you are creating the conditions that will probably keep the person away from you. Then they will exploit that and will tell you that, if only you embraced the Truth, well... That is blackmail and you should resist it.
I wonder if you will want to send me a PM.