Disclaimer: Look if I owned, I wouldn't have made Hawkmoth turn out to be who he was.
Max was not a big fan of love.
Love was messy, unpredictable and something better avoided in his opinion. Numbers, video games, statistics, those were things he could understand and break down, but love?
Love was something best left to others. People like Rose for example with her fairytale obsession and desire to spread symbols of it all around.
Unfortunately for Max, his heart didn't get the memo. Why else would he have fallen and fallen hard for the (taken) Adrien Agreste of all people?