No the MC is not directly involved if you want to know just play the game unless you want spoilers.
ah I see, then yeah that be NTR (just not for MC personally). And tbh... after reading reviews about this... I think imma skip, read that it goes a bit overboard with trying to be depressing that shit starts to be nonsensical.
One of the reviewers fav part was the stupidity of the MC almost NTR scene with the best friend character, and how everything in the game would be resolved basically instantly if they just talked to eachother XD
I don't mind depressing-ish games, but the full blown only depression endings... not exactly my cup of tea... although I am a fan of kara no shoujo (the second one, don't think I ever played the first)... soooo take that with the grain of salt XD (looking forward to the third part ngl). I did love the one "false" happy ending, but the true ending wasn't bad either, just not happy. That game fucked with my mind for like a solid week though... Was like "I don't know what to do with these feels."
One of my other favs, is katawa no shoujo, where the atmosphere most of the time is kinda depressing, with the shitty struggles of life, but finding something worth living within it (in this case a romance with one of the girls). The pick-none path with kenji was hilarious though.
He thinks you are gay cause you ignore all the girls and goes to accept your "love" and you back off, falling off the roof and die