"Jesteś miłością mojego życia" (pronounced "yes-tesh mi-wo-sh-cho me-ye-go zhi-tsia")
This translates literally to "You are the love of my life."
However, depending on the context and the specific meaning you want to convey, there are other ways to express this sentiment:
* "Jesteś moim całym światem" - "You are my whole world" (more romantic)
* "Nie wyobrażam sobie życia bez Ciebie" - "I can't imagine life without you" (more intense)
* "Kocham Cię nad życie" - "I love you more than life itself" (very passionate)
* "Jesteś wszystkim dla mnie" - "You are everything to me" (more general)
Ultimately, the best translation depends on your specific situation and the feeling you wish to express.