Hi OP, please do NOT do the apology face to face like Mokryna has told you to do! I am a Mil who has had some falling outs with my DiL, both to blame on different occasions, I also hate conflict, and much prefer to have time to digest important things than reacting straight away. I would hate my DiL to discuss something like that with me face to face, but I would really appreciate the apology in written form, and my chance to apologised back. Thank you OP for thinking to do this, if your MiL really is a kind person at heart, she will feel relieved, happy, and very grateful to you for doing that. My DiL that I have had some arguments with is very much loved by me, and I am so happy that I am able to tell her that these days. I miss her, my son and my GC so much during these lockdowns.