How can you tell if a relationship is broken, so broken that both of you can no longer fix it?

I think when you've tried & tried but end up with the same results. and you both just end up tired and frustrated, and the only thing keeping you together is the fact that you don't want the years you've put into this relationship to just go down the drain. You feel like you can still do more to save it. And even tho you don't get along anymore, theres still love there, and they're like family

And even if you're not quite as into them like you used to be. You're still afraid to see them with somebody else