Wife is pumping and I feel useless at night

My wife is exclusively pumping because breastfeeding wasn't working out for us. I'm happy to help and I do bottle feeds at night so she can sleep, which is great. But sometimes I feel like I'm just the delivery guy and she's doing all the actual work. She's exhausted. I'm trying to step up but I'm not sure what else I can do. Anyone else dealing with this dynamic? How do you make sure your partner doesn't burn out?