The expression 'I love my life' is 'Amo la mia vita' in Italian. The word for the verb 'to love' in Italian is 'Amare' and the conjugation of the first person singular (I) is Io amo. So you can use this to express your love for all manner of things. Often the pronoun Io can be dropped, and simply saying amo followed by a noun is sufficient. For example 'Amo mia madre' is translated into 'I love my mother'.
In your question, you mentioned using this phrase on stationery that you are having printed; using a phrase like 'Amo mia vita' is a great way to personalize and portray a positive and enthusiastic approach via your stationery.