what was my mistake ....

sometimes we bear the pain because of trust.we think they are only one main reason for our happiness. why we trust people and they became our special one.the person on which our trust first this person show care and love to us and when we trust this person and became close to this person this person start change their behavior

why you destroy my life
why you made my life hell
you know yes you better know
I was immature when I met you
you show me your love
you told no one can love me like
you were the person who told me you are an immature girl I am only one can you save from every harm.
you show me the love
I am fallen in your love day by day
you gave me the feeling you are only one for me. you have stolen my heart with your love
I am deeply in love with you.you said me I am yours. so why you forget all things now?what was my mistake why you changed you behave after a long-term relationship.I did everything for you I forgot my every happiness behind I just want to happy you. I forget my smile just because of you. so why you changed your behavior. what was my mistake? I can do everything for you. why you forget I cannot bear even your little mood swing. I don't want to see you in any pain so why you put me in huge pain. I love you more than this world. I trust you more than this world. you are only one for me. so why you changed your behavior I want to spend my whole life with you. you did a lot of-of promise with me where are your promises. how can you forget our memories how can you replace? tell me what was my mistake ?