if it was the other way around, do you think your husband would care?
Its part of how we are raised.. we except that all mums will be loved and favored, and dads will be second. So as a result dad's don't expect it. They expect mum to be favorite, and when the kid runs to mummy every time they don't feel hurt or upset by it.
But mums have the opposite experience, they fully expect to be preferred, so when dad receives more love, they feel rejected and hurt. Every week there are posts like this on here, with the same experience.
You just have to remind yourself though that it doesn't matter. Yes in the old days, women were the no.1 parent at all times, and generally became the most loved by their children. But now, we want and expect dads to step up and do 50% of the parenting, and as a result, "good" dads have a pretty equal chance of becoming the closer parent to the children (It is frustrating when it happens to "bad" dads).
Isn't that a good thing though? We want dads to do their fair share, and parent equally.. so we have to accept that dads have an equal chance of being the closer parents. Nothing personal to the mums, it doesn't mean their children don't love them, just like for generations of dads that came before it, it is just an inevitable part of the balancing of parenting responsibilities.
Personally I would just be thankful you have a husband who seems like they are doing well enough as a dad to become the favorite. So many kids grow up with useless dads - your kids are some of the lucky ones .