This paper provides an overview of some recent developments that were motivated by the unsteady interfacial coupling of existing codes. We describe the framework and the basic ideas first, which mainly rely on the use of a father model. Next we list the main achievements in this domain, and focus then on the interfacial coupling of a three-field model with a two-fluid two-phase flow model. Some numerical results are shown, and we eventually try to point out the main results and give some perspectives for further work.