When do you really know?

When do you really know if the love being given is real? Should you believe that after spending time with someone and giving that person your all but not being given your all in return that its truly love? So many people mistake love for lust, they tell each other how much they love each other but do they really mean it? It seems many times theres always one person in the relationship thats giving 100% while the other is giving 75%. Its hard to love so much that you cant realize that the other person isnt showing you the same amount of love, that you let the other person hurt you, call you names, abuse you emotionally and treat you like your "just another"
Many people in relationships love so much that they cant see behind the doors of that person. They love so much that they forgive the other individuals actions because they feel like forgive and forget is the best thing to do. They are so afraid of losing the other that they accept all their faults. When is it enough? When do you say stop? When do you really know that its love?
Do you continue to believe that the other person is going to one day change? Do you stay committed to this person because you love them but deep inside you feel so unhappy because you know that this is all wrong?
Some people dont realize what they have until its gone. They have a person by there side that supports them, loves them, is always there for them no matter what but they dont see it. They pay so much attention to everything and everyone else around them other then that person thats giving up their life for them. When is it enough? Well...its enough when you realize how unhappy you are and when you realize that your not being treated the way you deserve to be treated.
Its crazy because when you decide to walk away from the person its the hardest thing but it slowly becomes easier. The person then realizes that you were the one. What do you do then? Give them another chance? Continue to walk away? That answer is all within you, by using your heart, and your mind you will know which way to go. But remember a person that treated you unfair for many years its very hard for them to change. But maybe they will how do you really know?