The exploding growth of the number of mobile devices and their traffic demands indicate that Mobile Network Operators (MNOs) will face significant barriers serving their users with their dedicated spectrum resources. Spectrum reallocation for exclusive usage from MNOs is a time-consuming regulatory process making thus, imperative the need to improve spectral efficiency through new spectrum sharing mechanisms. This implies that towards 5G, the MNOs will need to use their spectrum resources in a cooperative fashion either with other communication systems (i.e. LSA sharing, unlicensed sharing, etc.) for covering the increased traffic requirements. In this paper we present a novel spectrum sharing mechanism based on fuzzy logic to facilitate MNOs to select the most suitable spectrum sharing option so as to cover their needs. The proposed solution is based on a novel coordination framework that enables MNOs and other spectrum license holders to exchange information about spectrum resources and realizes multi-option spectrum sharing.