Unbind GPU while system is running

Is possible (any method) to switch between Graphics Cards while system is running? And than disabled card bind to KVM/QEMU?

I have 2 GPUs (1x Intel HD 4600 and 1x NVIDIA GeForce 1060)

I would like to have virtual Windows 7 using KVM with GPU passthrough.

Intel Graphics for Linux (host) NVIDIA for Windows 7 (guest)

I know that i have to set stub for NVIDIA.

I would like to have primary GPU Intel Graphics and use sometimes NVIDIA card using Bumblebee (nvidia optimus).

But problem is that then i cant bind NVIDIA card to virtual machine. Is possible to unbind drivers while system is running? I dont think it is problem, because X server is using primary iGPU (Intel Graphics, not NVIDIA)

Thank you very much

PS: I have a desktop