Love is a strong emotion and one that's closely attached here to its opposite, equally strong emotion: hate. Jacob's hate for August arises, at least in part, because he's in love with his wife. He's also getting "close" to feeling love for the elephant that is technically is under August's supervision. Jacob might also hate August for other reasons, as listed in the quotation, but he probably wouldn't feel quite so strongly about August if he didn't feel so strongly about Marlena and Rosie, too.

Jacob already shows how much he's growing up here. He's already less interested in sex for the simple sake of it, in being turned on just to get turned on. He's already become emotionally invested in Marlena, so sex on its own has less interest for him. He's holding out for sex with an emotional connection. On a side note, it's funny that Jacob would see the woman in the sexualized comic as someone "with [a] horse face"; this could be the effect of the animals and other elements of circus life spilling over and consuming his mind.

This is an example of courage that isn't acted upon. Jacob knows what he should have done – stop the punishment of Rosie – but he wasn't able to. He thinks here that if he were truly courageous, he would have helped her. He blames himself for not being able to help her and laments his cowardice.