Henry has been in a relationship with his girlfriend, Alice Valko, since the third grade, and they are very close. Alice gave him the nickname of "Hank".
On the last day of his junior year, Henry attended a party with Ben. Alice asked him to dance, despite the fact that they'd broken up, but Henry turned her down. The episode ends with Alice discovering that Henry and Adrian slept together.
It is revealed that (when Madison Cooperstein calls him in Smokin' Like a Virgin that Henry has two younger brothers (that could possibly be twins) that share a bedroom with him. Alice confronts Ben, and tells him (Ben) that Henry slept with Adrian, and Ben, enraged because the divorce isn't final between him and Adrian yet, invites Henry over to yell at him. He tells him that he is no longer welcome at his house.
In Caught in a Trap Henry comes over to Ben's house and announces (via his outfit) that instead of college (or working at his uncle's swanky hotel in the Philippines), he will be joining the army.
Ben is angry and Alice shows up, proclaims her love for him, and offers to let him sleep with her before he leaves.
Henry declines, whereupon Ben calls for his dad. Leo comes up and congratulates Henry for the sacrifice he's going to ultimately make. He tells him that he will give him a job when Henry comes back and tells him to stay in touch.
Henry and Alice announce they are back together in the series finale.