At the beginning of a marriage ask yourself whether this woman will be interesting to talk to from now until old age. Everything else in marriage is transitory: most of the time is spent in conversation.
In countries where there is no marriage, there is no duty between husband and wife; when marriage comes, husband and wife live together on account of attachment; and that kind of living together becomes settled after generations; and when it becomes so settled, it becomes a duty.
Marriage was contrived for ordinary people, for people who are capable of neither great love nor great friendship, which is to say, for most people--but also for those exceptionally rare ones who are capable of love as well as of friendship.
Men and women -- even man and wife are foreigners. Each has reserves that the other cannot enter into, nor understand. These have the effect of frontiers.