This is a brilliant question to consider, as it shows you have identified that many of the tales discuss the theme of marriage and what it should be like. Tales to note for example are the Wife of Bath's Tale and The Franklin's Tale, both of which definitely seem to debate the nature of marriage in very different ways.
The Wife of Bath, both in her character and her tale, presents a view of marriage that is based on personal enrichment and advancement. She herself, we are told, has married five husbands and killed them all off with her sexual energies, and has done very well out of this bargain, as she clearly is a woman of some wealth and importance. Marriage is therefore a means of self-betterment, and, to be honest, has very little to do with love. The message that she presents in her tale is that happiness can be achieved if the man gives his wife complete mastery and domination, as shown by the way that the knight asks his wife to make a decision on the impossible choice that faces him. Giving his wife the mastery over him means that the knight is able to have his cake and eat it. The Tale ends with the Wife's own view of marriage clearly displayed:
And may Christ Jesus send us husbands who
Are meek and young, and spirited in bed;
And send us grace to outlive those we wed...
Marriage is quite obviously about gaining wealth and rising in the world.
In The Franklin's Tale, Aurelius and Dorigen, in their plight of finding themselves trapped in an impossible situation between honour on the one hand and fidelity on the other present a very different picture of marriage. First of all, let us remember that Dorigen deeply loves her husband and does not desire any extra-marital relationship in any way. When a strange twist of fate seems to force her to commit adultery, she is perfectly open about this with her husband and laments her situation. The way in which the purity of her love for her husband convinces Aurelius to drop his promise and not claim his rightful reward presents us with a very different view of marriage. Marriage in this tale is therefore based on sacrificial love and self-respect, a meeting of equals. This stands in sharp contrast to the attitudes to marriage expressed by the Wife of Bath.