Without knowing more about your particular situation it is hard to provide useful advice.
However, a generic way to resolve any sort of problem is to base the decision, whatever it is, on an objective criteria as opposed to a matter of opinion.
If there is no objective way, one can ask for one or three outside mediators with no particular interest on the matter and ask them about what they see to be the right decision and why think like that.
I had a dispute with a co-founder a few years ago and with the help of a external party we came to an agreement completely different than the initial solutions each of us had in mind.