How we cite our quotes: (Chapter.Paragraph)
Quote #4
Love, considered as an animal appetite, cannot long feed on itself without expiring. And this extinction in its own flame, may be termed the violent death of love. (4.71)
When Wollstonecraft says love here, she means sexual desire. She compares sex to a fire that can't burn for very long without going out. That's why you can't base a good relationship on sex alone, according to the wise Ms. W.
Quote #5
These are all preparations for adultery; or, should the fear of the world, or of hell, restrain her desire of pleasing other men, when she can no longer please her husband, what substitute can be found by a being who was only formed, by nature and art, to please man? (5.31)
If you only educate women on how to please men, what do you think will happen when habit and routine have made a woman incapable of pleasing her husband? Of course, she's going to look for some other man to please…
Quote #6
But what serious consequences ensue to rob man of that portion of happiness, which the Deity by calling him into existence has (or, on what can his attributes rest?) indubitably promised: would not all the purposes of life have been much better fulfilled if he had only felt what has been termed physical love? (5.148)
Men are so obsessed with physical love (or sex) that it practically becomes a religion for them. Pretty much everything they do is directed toward having sex, and many of them believe that their lives could be better if they'd had more sex in their time. They also tend to see sex as an entitlement that God has promised them.