Obviously, its not fair to them for you to disrupt their lives by attempting to relocate them because you have a new boyfriend...and their father is unlikely to agree anyway(and for good reason). So either you deal with commute or you move closer to your number one priority...which is your children.
Try talking to the lawyer and follow their advice. They are one who may give you the best legal advice and solution. The lawyer does not only work on cases but also provides counseling. The lawyer has experience of legal issues and can know the possible result of an action. You can try this out to read more about the lawyers.