I completely understand that feeling, in fact the husband and I went through a very similar circumstance. Knowing that we wanted to be together in the short term was easy; we were nearly identical and what a spark! But the longer term was much more difficult. I knew early on what I wanted, I've been around the block enough times to know what I want and need. He'd been hurt early and hadn't a lot of experience in dating and I knew it. We had one disastrous conversation early on about long-term expectations. Boy was that a mess.
So I kept my mouth shut, hoping desperately that he'd decide our relationship might go in the direction I wanted it to. But of course we couldn't talk about it. So I spent about 9 months or so trying to pretend that I wasn't hoping but unable to help myself. It was torture, but it certainly made for interesting times. Never a dull moment. And I wouldn't trade it for the world. I learned more about each of us, separate and together, in that time than I would have if we'd known where it was going.