I'm going to break up with my boyfriend for being a creationist
Is that a dealbreaker for you?
It's a big deal for me, I'm atheist
Those are definitely conflicting views. If you don't think you reach some agreement, it might be best to end things and find someone else more suitable for yourself.
My boyfriend is shit anyway.
Sometimes people just have conflicting views on life and their faith. If those beliefs are too contradictory then it may be an area of conflict and ongoing disagreement.  It might be best to find someone you universally agree with in order to keep the relationship in harmony.