The epitomator of Cassius Dio (72.22) gives the story that Faustina the Elder promised to marry Avidius Cassius. This is also echoed in HA"Marcus Aurelius" 24.
Syme 1988, p. 164. Syme, Ronald (1988). "Journeys of Hadrian"(PDF). Zeitschrift für Papyrologie und Epigraphik. 73. Reprinted in Syme, Ronald (1991). Roman Papers VI. Oxford: Clarendon Press. ISBN978-0-19-814494-6.