The problem is the non-standard 6.0mm plug the microphones use. Industry standard is 6.5mm (same as the headphone side of the headset), which is common to all large audio equipment.
This likely is a failsafe to ensure pilots plug the proper lead in the proper hole, but despite years of searching, ive never been able to find adaptors for 6.0mm plugs.
It would be far simpler to have a PC headset with 3.5mm plugs for your PC, and leave the aircraft headset for the aircraft.
I realise this does not solve the problem of wanting to wear David Clark headsets while playing flight simulator, but
that shan't be much of a disappointment.