You are my SIM card

A Lady asked her boyfriend " how much do you love me?

Boy: I love you so much, can't measure.......

Girl: No just tell me....

Boy: Okay I am like a phone and you are my sim card, there's no me without you......

Girl: aaaaaawww that is so romantic .......

(Boy says 2 himself) see mumu !! What if I'm a china phone wit 3 sims?