Can you say I'm literally in love with this house?

While this sentence is possible, it would not be accurate to say it. The expression "I'm in love with" can certainly be used in a metaphorical (symbolic) sense: you can say you are in love with strawberry ice cream, and people will understand you are just exaggerating to make a point; you do not mean you want to have a romance with strawberry ice cream. But the Word "literally" tends to mean factually, or Word-for-Word, so it might not be appropriate in the sentence you asked about. It is used like this: He takes the Bible literally. (In other Words, he believes every Word is true.)