To answer this question, we need to know the amount of matter in the universe. This will affect the strength of the gravitational forces resisting the expansion.
Think of the Universe as a balloon being inflated from the inside. The rubber of the balloon resists the expansion, providing a force against the inflation.
If our lungs are not strong enough to force more air into the balloon, the tension in the rubber wins, stopping further expansion. If we blow with greater force, the rubber may not be strong enough to resist the pressure from within, and the balloon will explode.
If there is enough mass in the Universe, the force of gravity will win against the expansion, slowing it down, either to a stop, or ultimately collapse.
If there isn't enough mass in the Universe, gravity will be too weak, and it will expand forever.