Stop worrying about how much history you have with him. Stop worrying about how much time you’ve spent together, how many milestones you’ve reached, how long you’ve been a couple.
You shouldn’t stay together because you’re dying to settle down and get married — and he seems like your best option. You shouldn’t stay together because you would rather stick it out with him than start all over again with a new relationship.
If he’s not the right person for you, it would be a mistake to stay. Sure, you might end up getting a ring on your finger. You might end up getting to walk down the aisle in a white gown and earn a key to your own home. But you have to stop and ask yourself what’s more important — reaching those milestones or reaching those milestones with the right person?
You don’t want to agree to spend the rest of your life with someone simply because everyone around you is already getting married and you feel like you’re running out of time. You don’t want to prolong a relationship that should have ended a while ago because you would rather be a wife than a single woman.
Having history with someone doesn’t mean you should stay with them. It doesn’t mean you’re meant to spend the rest of your lives together.
Sometimes, continuing your relationship would be a mistake. Sometimes, trying to make things work is the worst thing you could do. Sometimes, you have to accept it’s time to move on and let yourselves move onto bigger and better things.
You shouldn’t stay together simply because you’ve already been together for ages. Just because you know each other inside and out doesn’t mean you’re soulmates. Just because you’ve been through tough times together, and beautiful times together, doesn’t mean you have to go through your futures together.
You have to stop assuming you’re supposed to stay with this person, simply because you’ve already been with them for such a long time. You’re allowed to change your path at any point in time. You’re allowed to leave your relationship.
Instead of assuming it’s too late because you’ve already made your decision, you should take a few minutes (or hours or days) to think about whether you’re still happy. Maybe this relationship was the right one for you years ago, but maybe it’s no longer right for you. Maybe things have changed.
You shouldn’t stay with someone simply because you’ve already invested hundreds of hours into them.
You shouldn’t stay with someone simply because you’re ready for marriage and they’re your only opinion for settling down at the moment.
You shouldn’t stay with someone simply because you’re used to having them around.
Before you commit to this person for the rest of your life, make sure you ask yourself whether this is what you really want or whether this is simply the most convenient path to take after everything you’ve already gone through together. Ask yourself whether you’re happy. Ask yourself whether this relationship is right. 
