The presence of additional chemical equilibria in an otherwise simple system can induce unexpected phase behavior. We analyze the effect of this phenomenon on the wetting properties of binary mixtures with one self-associating component. As a first step we characterize the global wetting phase diagram of a mean-field lattice model for a simple binary system. We evaluate its reliability in generating an adequate topological description of bulk critical and wetting transition manifolds. These results serve as a basis to study the influence of self-association. We find that under appropriate conditions the appearance of new species in solution can lead to irregular wetting behavior such as "reentrant" wetting and "dewetting."