Does it exist?

So after years of being single and determined to stay that way, I find myself occasionally longing for a lifetime partner. A best friend, a lover, someone who I knows will always have my back no matter what. Someone who will be faithful mentally, emotionally, and physically for forever. Two forces joined together going in the same direction, picking up each other when the other is weak. The person who I know no matter what the world throws at me will be there to help me keep going. Someone to keep me in check, to inspire me to be more then I am today. Someone to lean on, someone to encourage me. A person who can count on me unconditionally. Does such a thing exist or is it all just a fairy tale?