It probably means that a woman's husband has to protect his wife. "Head" is the same as "lord" in terms of meaning: the husband should have say over what his wife does. Finally, "sovereign" means that the wife should treat her husband as if he were a member of royalty: a very important person. It also portrays the idea that the husband should have a lot of power within the family; much like a monarch has power of his or her country.
"To painful labour," later on in the speech, shows that the work that the wife would be expected to do would be hard and demanding of her. It could also refer to labour in the later stages of pregnancy, as the wife would be "used" to expand the family. "To watch the night in storms, the day in cold, whilst thou liest warm at home, secure, and safe," however, can give a slightly different view. For example, the husband would work through the day and night in whatever conditions, whilst the wife would be at home, also doing her work. It can be interpreted to show that women should be grateful for the fact that they do not have to work outside of their home as often or for as long as their husbands would do.
"Love, fair looks, and true obedience" is an indication of what the husband expects in return: love from his wife; a wife with good looks; and a wife that will do whatever the husband asks of her. "They are bound to serve, love, and obey" is another good quote, showing how women are "destined" to serve, love and obey their husbands.
The only reason that Petruchio attempted to marry Katherina, however, was money. Petruchio's theory is "where two raging fires meet together, they do consume the thing that feeds their fury." This means that two like personalities will cancel each other out, and, in this case, he will "tame" Katherina. This is in contradiction with the popular theory that "opposites attract," and shows the even two people who are almost the same can make a successful relationship.
