A smaller role performed attentively can help more than a larger role carried resentfully.

Willingness is part of the work rather than something separate from it. A large role carried with resentment leaks into everything around it: the tone, the corners quietly cut, the people who now have to manage your mood alongside the task. A smaller role done attentively delivers what it promised and costs nobody anything extra.

Be honest about which of your commitments you have begun to resent, and offer a reduced version you could do gladly instead. Say it early rather than at the point of collapse. Most groups would rather have your good half than your whole reluctant one.