I like to think that I am a pretty generous spirit and will offer to help people out when I feel I am able to, even if it inconveniences me (within reason).
I always put my family's needs first and would not offer to do anything that causes them unreasonable disruption, but find that DP gets into a massive sulk if I offer to assist anyone in a way that could possibly disrupt usual service (I do all of the cooking, most of the housework and we share childcare duties but I do more because I work PT).
For example, I am on a list of people to take care of a friend's 2YO when she goes into labour with second child. This could happen soon and DP has just started worrying that we might have to take 2YO overnight (even though this is very unlikely and I have said that I will do everything and expect nothing from him if that is the case). This is quite an extreme example, he has sulked over far less.
He is always volunteering me to bake things for family get togethers, give lifts to people (he does not drive) and I always accommodate these things the best I can.
I genuinely can't work out who is being unreasonable here - so please let me know your thoughts!
YABU - you should not offer assistance to others
YANBU - if it is causing DP minimal disruption he shouldn't sulk over it