I've always looked at Athrun and Cagalli as polar opposites... the former being so cool and collected but very doubtful.. the latter, however, is reckless, impulsive, acts on her own feelings, but is confident and believes in what she wants to believe in (without even thinking of the consequences)..
their similarities? well, the desire to protect the ones they love brought them to fight together in SEED, right? and eventually, they learned a thing or two from each other and somehow fell in love..
In Destiny, Athrun turned to be the impulsive one by going back to ZAFT because he was itching to do something about the war.. Cagalli wanted to handle her politics with coolness and calm but was eventually taken advantage off by her subordinates.. their relationship was put on hold after that because they needed some self-exploring.. but nevertheless, these two are meant for each other.
As for Meyrin and Athrun..........
man, i got nothing to say
