Some pieces.
Long-term relationships happen through lack of planning and foresight. If you're just "falling" into them, then see more women. Even if you're seeing 1, don't see her so many times a week that it becomes obvious you want more.
Each relationship has it's own "story"; one can't know the outcome or potential, and if you set expectations upon it, you will curtail it's growth before it has had a chance to live, and / or die.
It's your ego that fears hurting people. And moreover, your own feelings that not committing will hurt someone. Isn't it possible that committing to someone whom you're not totally interested is also a form of hurt? So it's possible that committing when you feel wishy-washy is also damaging. [Reframe]
Keep in mind LTR's are reserved only for the *best* of women. If you keep high standards, you'll prevent yourself from just lazily falling into routines.
Lastly, just man up and state what you want. If you're not getting what you want, you're not living your life according to your goals, you're living someone else's. So, there's no way to dodge the bullet of stating what you want and potentially hurting someone. You don't have control over how they feel.
A-Unit