I know that over time and the course of three major moves, my husband and I have become best friends. It's hard keeping a 'best friend' as close when you have been away from each other so long (the last time I saw my longest/best female friend was almost five years ago and she's in Missisipi now, so we email a lot but it's not the same) but my husband is there for me.
Do I think that your spouse SHOULD be your best friend? Not really, it's just the way it worked out for us. I think it's good to have a sounding board outside of your relationship sometimes (my co-workers,lol) but I do think it's good to have your husband as friend, something my parents never did and wow, did it ever show.
I think that is one of the reasons why my mom loves my husband so much, she sees in him everything she never had in my dad.
