That's true, it was a small lie but his lies from the past have been whoppers--specifically about their financial standing. So if dishonesty is a hot button issue for her, then he needs to be especially mindful of that and act accordingly.
I don't think it's so much about the actual fib, but the history they share together. She doesn't trust his word, so he needs to take extra precautions to make sure that he is truthful with her.
