I would like to know the meaning of the next sentence.
And I don't know where you....
It doesn't mean anything because we don't know what she's starting to say and also it doesn't matter what she wanted to say.
The point is that she's angry and he interrupted her with "I love you, mommy", which immediately made her stop yelling/being angry. That is, it doesn't matter what he did or why she's angry -- "I love you, mommy" is a like a magic get-away-with-anything phrase.
And also the last panel implies that the dad uses "I love you" to get out of trouble with his wife too!