Can you stop being with Haley or do you have to no matter what?
No. If you play the game, there is no way to avoid Haley.
You can make choices that gain points for Haley. But these points have had zero effect on anything so far. I suspect they will have an effect on endings, but you'll have to play through the entire game to get to the point where the MC may not have Haley as his main love interest.
You can have the MC pursue other girls. That will affect scenes and conversations with Haley. But the MC is always with Haley, irrespective of any side-piece(s) he might be getting.
Haley is number-one in the MC's heart, and she feels the same about him, only more so. They are lost without each other. That is the basic premise of this game. Everything is written around that immutable fact.
Not playing the game does work though. I recommend that choice.