Does madhy (pre-seminal fluid) discharge due to conversing with one's fiancée online during Ramadan invalidate the fast, and does it necessitate making up the fast or offering expiation?

The discharge that exits when thinking about lust might be madhy (pre-seminal fluid), which does not invalidate the fast. It might also be maniy (semen), and there is a difference of opinion among scholars regarding whether it invalidates the fast for someone who caused its exit by repeatedly looking. It is more prudent to make up that day. It should be known that it is not permissible to speak with one's fiancée before the marriage contract, because she is a stranger (non-mahram).