Let's be honest, no one really wants to be alone. I don't care if you're the biggest player out there or love feeling free, there are always going to be nights you wish you weren't going to bed alone. Or, you could be that person who loves attachment and craves attention from anyone who is willing to give it to you. Whatever type of person you are, there is no excuse imaginable that would make being in an unhealthy relationship okay.
If your significant other does not quite literally kiss the ground you walk on, when you would cross the ocean for them, they aren't worth a second more of your time. You deserve better than someone who is barely doing the bare minimum for you. You deserve the love you're giving and there's no reason to settle for less.
Knowing you deserve more and not doing anything about it might be the most disrespectful thing you could do to yourself. Later, you're only going to regret wasting so much time being unhappy when you could have been taking that time to become independently happy.
Deciding to walk away from someone who you invested so much time and effort into is never easy, everyone understands that, but no one understands why you're holding yourself back when you're aware of that fact. It's going to be hard at first, but in the end, you know you did the right thing. Don't think of leaving as giving up, but that you exhausted every effort you had. If you've gone above and beyond for someone and they won't reciprocate even the slightest, even after verbalizing your feelings, there's nothing more that you can do. It's not your fault that you have to leave.
It's truly unhealthy for you to stay in a relationship that you only give to, but never get anything from. A relationship takes two and there's no way to compromise that. If your S/O isn't willing to do what you would do for them, it's already an unequal relationship. If their actions don't match their words, don't trust that they're going to be there. You should be able to count on your S/O, not hope they pull through for you this time.
Don't be afraid to move on. There are good ones out there, I promise.