My friend drives us to football but wants to leave early. Can I make a separate plan home without offending him?

At 1–1 with twenty minutes left, my friend tapped his car key against my arm. "If we go now, we'll beat the queue." I followed him out and heard the crowd roar before we reached the car. We didn't know who'd scored until he checked his phone.

We buy our own tickets, and he usually offers the lift. I contribute towards fuel. I hadn't realised when we started going together that leaving early was part of the arrangement; lately he's said he won't sit in traffic for a game that might end in a draw.

There is a later train I could take home, with a walk from the station. For the next match I'd like to tell him beforehand that I'll stay to the end and return separately. I don't expect him to wait.

Would that sound ungrateful after months of lifts, or is it a sensible way to stop having the same argument in the stands? I'd still enjoy arriving together. I just want the ticket to include the last twenty minutes.