I think 'Fellowship, companionship, mutual help and comfort' and 'To grow in selflessness and to love you spouse and his/her family as your own which then becomes the stepping stone to love everyone else' would be nice but probably not the true aim of marriage. 'Procreation for the propagation of family lineage' is probably more likely for most cultures.
I think many people actually get married because they feel obliged to be accepted by society. However, I wouldn't like to call that the chief aim.
Thanks for the vote and upvote, @spectrumecons.
We could approach this question from many angles (cultural, philosophical, economic, religious, spiritual and so on).
Hopefully that will make the answers interesting.
Thanks again for you input.