He needs a father who reminds him to bring his lunch, pack his bag, wear his jacket, get enough sleep, etc.
A terminally-ill woman must deal with her ex-husband's new lover, who will be their children's stepmother.
It must be tough living in a house with two guys.
That is the role you need to play for your stepson.
Stepkids pick up on these feelings and often act them out on mom's behalf.
But even if he were attracted to you in that way, you are a role model, mentor and authority figure to your stepson.