Theory is difficult, isn't it? The biggest problem, I think, is that trying to cover broad areas of theory in any depth in one semester is confusing. To understand any theory, you pretty much have to immerse yourself in it.

Is this a first year course? If it is, the relevant theories will be covered in any readings you've been assigned. That'd be the first place to check.

Bell Hooks is a pretty easy-to-read lesbian/feminist theorist who is against marriage in general. She believes it's unhealthy for our society.

I'm going to check for some scholarly articles that might help.