It sounds to me like he needs your undivided attention right now. If you have no other partners right now I think I would concentrate on him and spend more time with him. Work on creating a solid foundation that you both feel good about.
Poly works better it seems if both people in a couple are able to have their own lives going on. Perhaps he could work toward becoming involved in things he loves to do so that when you are both ready for you to pursue other people, he will be off doing his thing too and the time apart will be good for both of you. Time management is a skill. It sounds like now is the time to practice that before you have another partner.
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