I had one of those, too. He was supposed to be my out. He was a year ahead in school, and was heading off to college and I was going to follow. Once he was in college, my mom sent out the local elders...Between the local elders, my mom and his misplaced love for me, he converted. We broke up, I left the religion after my first year of college and he ended up marrying our classmate's mother.
That plan really backfired (for him, unfortunately. My biggest regret in my life, thus far, dragging him into the cult). But I ended up walking away 100% on my terms and on my own volition.