Since this imples an exchange, you would use "por" for this sentence. "Mi vida por tu vida".
La vida is the life in spanish.
'La vida contigo' is the Spanish equivalent of "Life with you".
Lleno de vida is the best way to say "full of life" in Spanish.
your life = tu vida
You can say "la vida".
In Spanish, to say, "You are my life," you say, "Tu eres mi vida." For example, if you want to use it in a sentence you can say, "Tu eres mi vida, y me amor." That means, "You are my life and my love."
Mi amor por la vida is "My love for life" in Spanish.
A la vida.
La Vida.
Mi vida.
Que vida!
La Vida.