The Mothers by Brit Bennett
I’m not a big fan of “cheating” in love. I don’t think it’s honorable. So it’s hard for me to read about it & think “oh well there ya go, that’s an ok reason to lie and hurt people.” But having said that, this happens to be the story line in this book. It’s a well-written love triangle that goes on for decades because two friends love the same man and he them…. and they lie to each other until they don’t. It doesn’t seem to matter why the triangle happens, but it never ends differently.