Because you are a caring, considerate person, who likes to see the best in everything. You don't like to give up, especially on something you love so dearly. That's okay, because that shows resilience and loyalty, You don't run away when times get tough. The problem is that you're not showing this care and consideration to yourself, and if it's toxic, the other person isn't showing it to you, and possibly towards themselves too. They take your good nature for granted. They feel that you will always be there for them no matter what...until one day, you aren't. It isn't because you don't want to be, because once you love someone, that's it, you can't undo it. Its because you've reached your limit, you've given all that you could and now you're empty, and have little to give. Your tolerance levels waver, and soon it all becomes your fault because you allowed it before, and now you're not allowing it. It confuses them. You're not who they thought you were. They overlook that you have withstood a lot of pain, torture and confusion, all in the name of love for them. They don't quite see what you've gone through to let them live how they're like. In their heads, you chose to do that, so they believe they are not at fault. In your head, that's just how you love. Toxic relationships inhabit a lot of confusion, pain and suffering - more than you should deal with. If it doesn't feel right, cut yourself off. You decide your worth and how you're treated, not someone else. You deserve someone who sees the good traits of you, not someone who sees them as easily manipulated and disposable. You deserve someone who gives you just the right amount of love and care back.