My 2 sisters and I all married our birth order matches. I'm a youngest married to a youngest. We get to deal with our siblings' bitterness about how much easier we had it growing up! Yay!
Being the oldest being married to a middle is very peaceful. He makes me more laid back and I kick his ass in gear I think conflict resolution is much easier, too.
I could never be married to another oldest. I think it would be ww3 all the time and a youngest would be too carefree for me lol