In our world of physical realities, the plethora of emotions or even responses to stimuli received is entirely a matter of choice. (Received being the keyword here). You need not receive or internalize anything that’s outside of you. Conjure this if you may; an argument with your spouse leads to you saying he/she hurt your feelings. Is that possible? Even remotely? No, and here is why.
Your feelings are yours and yours alone. What someone else says or does cannot be the basis of your response or of consequence to your feelings, because to feel good, bad, injured, insulted, wanted or happy are a matter of your choosing. Not any other persons, or any other external factors. So, as long as you hold all people around you responsible for your feelings, good, bad, or ugly, you are going to remain a product of their treatment of you. Not your treatment of you. This means if they choose to treat you bad you remain feeling bad and hurt.
As for holding in you, the emotion of hate for someone from five years ago, that again is something you have elected to do, consciously at first and then it becomes a sub-conscious response of hate towards that person. Does that hate you hold within, affect that person? Not one little bit. The only person it affects is you, in your behavioral patterns and the limitation of your personal growth. Finally, keep in mind, it is you who holds the keys to your happiness, sadness, bliss, or anxiety, so do not give those keys to someone else. This is easy, if you love value, and respect yourself sufficiently, you will love, respect, and value your opinion first.