He starts out viewing women as objects for his pleasure and don't consider their opinion in his actions. In his relationship with Melanie, this view of women cost him his job. In this professor-student relationship, David pressured Melanie for sex when she didn't really want it. However, this does not justify the inquiry committee firing him from his job. By law their sexual relationship was legal and technically it wasn't rape. He refuses to admit he is wrong because he believes that he wasn't wrong. Melanie did accept his offers readily. The only thing wrong David could've happened is that Melanie had a boyfriend.
As he spends more time in the country with Lucy, his view towards women changes. Especially after she is raped, David treats women with more respect. As a white man, he is privileged in South Africa. Even though apartheid is over, he holds a position of power, although it makes him blind from the opinion of others. If he were to stay in Cape Town, his views probably would not have changed. He would've had no consequence for his actions and he would've thought that everything that he was doing was okay. He also would not have built his relationship with his daughter that was key to changing his view on women.