Catullus 72

In this poem, Catullus talks about a lot of different emotions, and those emotions are what balances the poem out. The basic meaning of this poem is that Catullus, inevitably, gets crushed by Lesbia's cheating actions. I say that it was inevitable because if Lesbia was capable of lying to her foolish previous husband back when she first liked Catullus, then she is certainly capable of lying to Catullus about someone else. That's the reality: that anyone is capable of anyting.
Catullus says in the poem, "Because such an injury as this drives a lover to love more and respect less." I believe what Catullus is trying to accomplish through this sentence is that no longer does he fully repsect Lesbia for cheating on him, and maybe he does not trust her as much either; but he will try harder/"love more". It's like he's saying he wants her more because she cheated. Obviously Lesbia wasn't happy with Catullus or wasn't getting what she needed - which is the case with some couples. Therefore, she found it with someone else. This makes Catullus want to work harder at the relationship. I understand how Catullus feels though, like maybe if he works harder he can forget that Lesbia cheated on him and it will all work itself out. But in the end, that doesn't always seem to be the case. Sometimes your opinion of the person is so completely warped after an incident such as that that you can't ever look at them the same again, thus being forced to end the relationship.
As for the balance of the poem, Catullus does a terrific job of using different forms of words to show that the balance in their relationship is off and therefore completely changed. What Lesbia has done has changed the balance - the passion, now, is more intense, but the respect has gone down, throwing the "scale" off balance. Some examples of balance words he chooses are: "you only knew Catullus.." and "Now I know you."; as well as comparing Catullus and Jupiter in the sentence, "...and that you would not even hold Jupiter before me." With the latin words, he uses words such as amare, which is an every day kind of love; vs. dilexi, which is the real love that one cherishes. By doing these things, it shoes how conflicted Catullus was and how he realizes everything now.