Quote 1
"Why do you own such a horse?"
"Ah, well may you ask it! It was my fate, I suppose. Tib has killed one chap; and just after I bought her she nearly killed me. And then, take my word for it, I nearly killed her. But she's queer still, very queer; and one's life is hardly safe behind her sometimes." (8.12-13)
Alec uses "fate" as an excuse for owning a horse that occasionally tries to kill him when he's attempting to frighten Tess on the carriage ride to The Slopes. And the strange thing is, Tess seems to accept his answer – "fate" is real to her, something that can be called up to explain the unexplainable.
Quote 2
"I couldn't help your seeing me again!" (56.107)
Alec argues that his meeting with Tess again after so many years was fate, and that it means that they are meant to get back together. Tess still argues against fate, and insists that it's free will, and not fate, that makes the world go round. Of course, once again, her will wasn't consulted in the matter: she couldn't "help" that he saw her again.
Quote 3
"Remember, I was your master once! I will be your master again. If you are any man's wife you are mine!" (47.39)
Alec is angry after Tess smacks him with a heavy work glove, and he actually says what he thinks: that he has some kind of natural right to Tess, just because he's the first man to have had sex with her. In his mind, this makes him her "natural" husband.