Husband and mom not getting along 3 weeks before the due date

Torri • Wife, teacher, Mama, Baby girl Jan. 2018 🎀 Baby boy June 2019 👼🏻 Baby girl July 2020 TTC #4

My mom and husband have struggled on and off in their relationship from the beginning. My husband can be very confrontational at times (usually always with the best of intentions but it can turn into a mess in the process) and this greatly upsets my mom and she takes weeks to move forward. Well on Christmas <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> my husband very calmly confronted my brothers “girlfriend” (the woman who he had an affair with and really is just a piece of crap in my opinion) and it of course upset the girlfriend and my brother and in turn my mom. (Mainly because it was Christmas <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">eve</a> and there were little kids around). My husband is not sorry he confronted her and honestly I’m not either, but my mom is very upset that he did. I’ve explained to my mom my position and my husband did apologize for upsetting everyone, but now my mom is very upset with him and I’m worried that this tension in their relationship will be a detriment as we get close to baby’s arrival, (Only 3 weeks til the due date), especially since my husband and I decided a long time ago that we don’t really want our families to play an active role in labor and delivery (they are aware of this). I’ve talked to both of them and my husband understands where he went wrong in the process, but my mom is still mad at him. Any advice on how to handle the situation?