Every relationship demands sacrifices. Every relationship demands adjustment. It is give and take all the way. Some call it compromise. Others call it negotiation of needs. Whatever you call it, the truth is that we accept what our partner wants despite our being against it and vice versa many times.
We all have our values. There are certain principals by which we live. We have acceptable and non-acceptable adjustments. Ask a green activist to adjust to killing of whales. He/she would never do that. That is unacceptable to them. That goes against their value. Similarly for some people any extra marital love is totally unacceptable. If they find out that their spouse was involved in one, the relationship may break. It is simple - I will never compromise on this set of values that I cherish.
As I said earlier, every relationship is based on give and take. For example I may be in great and passionate love with my partner. If he/she wants me to compromise on my values what should I do? I have two options. If he/she does not agree, I will either break my limits or break the relationship. Say, I break my values. What will now happen to my relationship? I will begin hating him/her for making me break my limits. I may wonder - why he/she could not respect my values? Does he/she have no respect for what I think and value? Why did he/she insist that I break my principles? Why cannot he/she adjust and agree to my point of view?
Any compromise on highly cherished values will doom the relationship soon. You will be a loser both the ways.