Having a belief in the relationship is one of the most important factors in ensuring its longevity and stability. Just like people need to have confidence in their own abilities, you need to feel that you and your partner make a great team in the relationship. Your "team ability" could be about anything, even being able to make a decision on where, and the type of date to have. If you can't even make a deal like that with your partner, you might have problems in the future.
If you do not feel that you and your partner make a great team, then you might need to think about where this relationship is going to head to. You need to ask yourself (and maybe your partner as well) why things aren't working out for you, and what would you need to change in order to become a great team? Two people that are in love need to be able to solve any kind of obstacle together.