He doesn't love having sex with her. He has managed to hide this from Jen by effort of main will. He's young and fit, but it takes him forever to come because he's so unexcited.
She misreads this. For her, a man who takes half hour to come is a hero.
The man she loves is the man his friends sometimes call gormless. She doesn't know the man who forces balls past goalposts as if by concentration, who feels implacable hatred for his opponents. She doesn't know he hates her lack of make up, her ordinary body, her ordinary face. Sweet, nice Kevin does know, but it is this Kevin who won't be able to tell her.
So he mugs and smiles, and waves through the separating glass as if saying goodbye.
Car 5 map