They're unrelated concepts. Cheating on his wife isn't "disrespecting women", it's disrespecting
his wife. I agree it's a shitty thing to do, but it isn't about gender at all.
http://www.dictionary.com/browse/feminism
noun
1. the doctrine advocating social, political, and all other rights of women equal to those of men.
2. (sometimes initial capital letter) an organized movement for the attainment of such rights for women.
This really isn't a complex concept. If you think women should have equal rights, you're a feminist.