I would say yes. You should at least discuss it with him. I would tell him that you are sorry that you let your emotions get away from you like that and none of you should be fighting in front of any of the kids.

Tell him you will try your best to NEVER let that happen again.

Out of curiosity, what caused this big fight in front of all these little kids?

H and I fought in front of our kids once a long long time ago. We both sat down and apologized to them and told them that even though we fought, we are still a unit and we love them very much. Then we answered their questions about the fight and reassured them some more...we were all crying about it because the emotions were SO high. But they really felt better and safer after we made it an open discussion. It helped them understand that just because people right and get angry doesn't mean bad things will happen after that...we tried to help them understand that fighting leads to making up and getting feelings out in the open.

It's up to you but I think it's always good to talk to kids after they've witnessed adults fighting.

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We don't see things as they are, we see them as we are. ~Anaïs Nin

I guess I don't see anything wrong with apologizing to SS11 for making him witness it. It had to be uncomfortable for him, and it may offer a good opportunity to talk about what BM is telling you he feels. I don't imagine an 11-year old boy would say "I wish BD would stand up to SM but I don't think he does because it'll cause problems...". If it truly came from him it would've been more along the lines of, "SM always thinks she's in charge and BD never says anything."

You might ask him about his thoughts or his perception of things. Express to him that you want him to feel like he can share his feelings with you and SD, rather than you having to hear it BM.

Maybe just tell your SS your sorry he had to see that and be present for it. I explained to my DS once when he saw me and EX fighting that sometimes adults argue and yell too, just like kids. Sometimes we say things we shouldn't when we're mad that we don't really mean. And that I was sorry it scared him. That's all I said to him and dropped the subject there. He didn't ask anymore about it so I felt like he was content with the explanation.

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... why would you feel worthless and weak? You gave everything, your entire heart.. giving it to him. To truly give your heart, your trust, is taking the bravest of all risks--C.Young

I'd say yes.

Kids learn by example, and when they see adults take responsibility for their actions, they learn that they need to do so also. When he's older, he'll remember which adults in his life took responsibility for their actions, and who did not.

ONe suggestion: Try, if at all possible, to not go to the exchanges and definitely don't let your kids go. The less of BM and her SO that your kids see, the better off everyone is.

I think it's a good idea for him to see you take ownership of your part in the mess. It shows maturity and that it's good to talk things out. It will be a good thing for him to hear

"There are two things over which you have complete dominion, authority, and control over - your mind and your mouth".

I have to agree with what everyone has said. I would apologize for it. Maybe DH can be part of the discussion too?