If this is so important to you, then you have to tell him. Don't let him push you around to do things that you aren't ready for. You have to tell him why you are concerned and maybe what you two can do together to solve it.
I understand that you fear that this could cause a breakup. But if this is what is best for you and you really want to have a more security, then don't let a guy ruin that for you, even though you love him. Do what is best for you.