Flip my feelings with a switch?

Sometimes i wish i could turn off my feelings with the flip of a switch, so many people who have come into my life have done it. They come into my life saying they are different, saying they will stay with me no matter how bad it gets. Then when they found someone better they expect me to switch off my feelings for them, but before i figure out even how they are already gone from my life. After that i get accused of obsessing with the past, i'm sorry if i don't have the ability to just forget everything someone asked me to forget at the flip of a light switch. I actually have a heart, contrary to most people it seems..