Alex is Max's "ex". The situation is complicated, and is the events leading to Max's transformation into Dead Max.
December was when Alex and Max's troubles began. Max admitted his love for Alex to him, only to be rejected with barely an explanation. Max cried the whole way home.
The rest of the month Alex and Max barely talked. Everything was awkward. Then they finally moved on. They were finally comfortable around each other, Max could finally deal with not having the love he wanted so badly.