Don't know what to do with my child's father?

Me and my long distance bf have been together for 3 yrs we have 2 kids. He lives in Canada me in Ohio he come to visit for months at a time. He is a good father but he is not very nice to me always doubts my feelings for him I try to break up with him but he wont go. He recently asked me and the kids to come to his country for Christmas this year ad to meet the family. He wants us to stay for 2 months but when I ask ca we move there with him he says he wants to finish college. He does not want to live here even though he said he always wanted to. He also said if I did not want to come the kids are. I feel if I go he will try to keep the kids and they will not come back with me. I don't know what would you guys do? He is a good dad and he gives us whatever we need but I just don't know. Would you guys move on or stay?