Focus on the now and how you're feeling. Try not to think too much about what may happen. It will make you crazy and there's very little you can do about how the future will transpire anyway. Keep talking with your partner. Talk about your hopes and dreams as well as about your fears. Be happy with yourself and become your own primary (there's a great deal of strength in knowing that even though your preferance it to be with someone that you'll be just fine all by yourself).
Everything will be ok in the end. If it's not ok it's not the end.