"people marry the one who loves them the most, not the one who s/he loves the most" - what do you think?
As for your quote, i think not(want spend life without X) = want spend life with X. The two negatives cancel out. So it doesn't really makes sense to say: Not X, but X. It's all X!
I've always seen it as marrying someone I know I can spend the rest of my days with even when he drives me nuts sometimes, because I can still look at those times and honestly say, 'it's good.'
Well, your living right now, you've had happy moments in your life no doubt, your breathing and surviving, so I don't think there is anyone you could not live without. It's all about who you want to live the rest of your life with.
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