Your relationship has been going great for the last couple of months or years, then suddenly your partner becomes cold toward you. If there’s been a sudden change in behavior and your partner is acting like he or she is sleeping with the enemy, there could be some unresolved hurt and anger that needs to be addressed. Once resentment sets in, it can seriously impact the health of a relationship. Psychologist Jeanette Raymond, author of Now You Want Me, Now You Don’t! told The Cheat Sheet resentment often arises when a couple’s relationship expectations are not being met.