I have two children with my boyfriend, and I'm trying to follow God's plan. I want to get married and he doesn't. He also doesn't want me to leave with our children. What should I do?
Following God's plan doesn't include living with a man and having children without being married. I assume you recently decided that you were going the wrong way in your life and are trying to get back on track.
Your boyfriend wants to have the benefits of marriage while only pretending to be married. If he isn't interested in marriage, then he has made it clear that he isn't interested enough in you to commit himself to you for the rest of his life. Therefore, you have to decide if following God and receiving heaven as your eternal abode is more important to you than having a live-in pretend husband. If God is most important (and He should be), then it is time to move out and eventually find a real man.
So long as you remain hesitant, he has no reason to change.