Okay I think I understand the potential issue now. Are you using speakers or headphones to listen to your friends? Because if you're using speakers, then the microphone will be hearing their voices too, and while they won't be very loud the noise gate is probably detecting them as if they were your voice and so leaves the mic on all the time when *anyone* is speaking.
An easy way to deal with this would be to use headphones when chatting with people, and make sure their voices come over headphones. That way the only voice your microphone will be able to hear is yours not theirs, so the noise gate should block everything other than you speaking.
If I understood your problem correctly then I had the same issue a while back when I used to game with friends and we'd be on voice chat together. I also had software that would detect when I was talking - but because their voices came over the speakers, the software thought every time *anyone* talked that I was talking, and so my mic would just be going through the whole time and annoying everyone.
I initially fixed this by using headphones, but I had crappy headphones at the time so I switched to using push to talk instead and assigned one of the extra mouse buttons on my mouse to be push to talk so it would be easy enough to press mid game in FPSes/MOBA etc. So yeah in short try using headphones
