Just as you get to decide for yourself what you want sexually, he gets to decide for himself. I would gently ask him about his previous intent to see a therapist about this decision and remind him it is a little too late to wait until marriage with you since you have already had sex together. However, if he wants to continue waiting, that's his decision and all you can do is decide if you love him and want to wait with him and get to know him and understand this point of view of his or want to move on.