AITA for not wanting to pay my roommate money for using his subscription?

So my roommates and I all use each other’s streaming services because we all watch them together, and for HBO Max we’ve been using his. Today he found out the account was attached to his credit card, not his parents. All the other accounts are family accounts from parents. He asked us to split the cost with him ($135) (4 ways) from the past 7 months because he didn’t know the account was set up to his personal credit card, not his family’s. I feel bad and that sucks, but is it my fault he didn’t know that? I check my bills and statements at least once week.That’s no one’s fault, but he wants us all to pay. Should I pay the full amount? I suggested we split half of 135 (67.5) 4 ways instead. But lowkey I don’t even want pay that. He is way richer than me also and has a 6 fig job after graduating from college and I don’t even have a job yet (we’re 22). I feel like he can spare the hit. Why should I have to pay because he hasn’t been checking his bills for 7 months? We would’ve stopped using it and had him cancel if we’d known it was being personally charged to him, not his parents. I’m going to pay it because we’re friends and it’s not that much $$, but I’m just wondering about the principle of it.