How did you get from "knowing someone personally" to "spending your life together"?
I just saw a sticker saying "sometimes you meet someone and from the first moment you know you want to spend the rest of your life without them" and decided to stick it in to my argument, but I agree - it didn't come out right.
Basically, a persons personality is a huge character trait, which tells you much about him, which you can only see if you meet him in person. Hence "knowing someone personally" must include meeting them in person.