I've never read de Beauvoir, but I think I ought to. It looks like she's interested in sexual love as a context for authenticity and overcoming the estrangement between self and other. This overview of her work has lots of interesting leads. I like the phrase "the truth of the erotic event," though I doubt it would go over well if you had your students reading her intro to de Sade's Justine. Maybe something from The Second Sex?