You can't really do all that on your own, you need both people in this working together towards something so you can both grow together. Him joking about this is kind of alarming to me, seeing as how he doesn't take the seriousness in this situation. Maybe he doesn't realize the consequences involved and thinks that problems in the future will just solve themselves? I don't know, but I was once like that so I can certainly understand his mentality even if I don't agree with it now.
Keep in mind that if you guys do break up, it's going to hurt no matter what. He is unique in his own way and there are some things about him no other guy you will meet can match. But he is not the only guy in this world for you and you will meet somebody else no matter what happens. Everything will be alright. Hurt is a part of life and I think you will grow from this experience no matter what happens. If you are still honestly having a good time with him, which should be priority one in a relationship right now anyways, then keep it going and cross that bridge when you come to it in the fall. If you aren't enjoying yourself or finding yourself as happy as you used to be with him, maybe a split right now would be good for the both of you. That's not an easy choice and it takes alot of guts, but you have to really believe in yourself and have confidence that you will be happy with somebody no matter what. Trust me on this.
Waking up next to a beautiful girl,
Step outside and say hello to my beautiful world.