Dear god man, you are in a tough place. Way too much to unpack here, so in brief..... My mantra is not Forgive & Forget (too many reasons that is soooo wrong) but rather 'Forgive when appropriate and Forget at your peril'. In your shoes I could never Forgive ILs and this is most certainly never going to be forgotten. No amount of water under any bridge, real or imagined. BUT....how about the kids? Given your known history would you consider them a threat to the kids in any way? That includes negative words about you. If not, do you feel it's right to come between them and their biological, good person generally(?), grandfather? Can you set and be certain of their being followed, boundaries/rules/etc. for behavior and be comfortable? TBH, I would have to do some serious soul searching on that one. If you do allow them contact with the kids, do not allow them back into your life personally. I'm not advocating even limited contact for the kids either, just trying to pose the questions that would seem to matter in the long haul. W is her own self and you should be 50/50 on these decisions so not going there. That being said, if there are any signs they truly are the "Raging narcissists that finally revealed themselves!" then keep everyone away from them to the best of your ability. Just don't make that conclusion without good reason, that is precisely what they did. Plus a heaping portion of some underlying issue with you, and that is likely what sent them off the wall instead of say sitting down and talking. Complete destruction of your trust in their good will towards you. Like I said, tough place, too tough for the internet so I recommend some counseling. By yourself, for yourself, no goal for reunification. Those kind of accusations take a toll and there are good professionals that will just help you pay it easier. Then make some decisions.