Relationships change, that is inevitable, because people themselves change. Those that don't change die.
Your relationship reached a crisis point. If you fail to adress the crisis, it will fail. But if you manage to solve it, it will strive, because it will have become deeper. Probably the current crisis is due to the fact that both of you are behaving more naturally than before, and each one of you is having trouble coming to grips with the newly apparent aspects of the other,... The key to solve this is to get to know and accept the other, while making compromises on certain aspects of your relationship. You also have to learn to deal with conflicts whithout ending in violent arguments.
The good point of passing this crisis point is that you will be able to behave more naturally with your partner, and know that you are being loved for what you are, and not because of you partner's illusions about you.