As time goes on we're either "growing together" or "growing apart".
Before any dramatic decisions are made it's important to discuss your wants and needs with your mate. Communication is the GPS for relationships.
Having said that I believe each of us is responsible for (our) own happiness. You get to decide who you want to spend your time with. If someone is unhappy in a relationship and they (choose) to stay then they are (choosing) to be unhappy.
I don't believe in staying together just for the sake of staying together. If you are not "in love" or you feel the urge to cheat on your mate it's best to move on. Although everyone will tell you to end one relationship before starting another not many people approve of breakups or divorces unless there is some type of "abuse".
Only you can decide what is (right) for you. You don't need to be abused or mistreated to give yourself permission to end a relationship. If you are unhappy don't rob yourself or your mate's time by going "through the motions" when you both could be with others where there is a (mutual) desire to be together. It's not about "right" or "wrong". It's about "agree" or "disagree". Ultimately we are all looking for someone who (naturally agrees) with us on the major things in life.
"There is no amount of (work) or (communication) that can overcome being with someone who does not want what you want."
There are only two ways to experience joy and peace of mind in relationships. We either get what we want or we learn to be happy with what we have. The path you choose is up to you!