K.K.
Hi A.,
I have to say that there are two parts to this story. There is the part where you husband needs to grow up as the other mothers have said, but your children need to learn that there are consequences for their actions and "I'm sorry" doesn't always make it better.
That being said, there is an old adage..."Time heals all wounds". What you have to focus on now is not giving your children a victory, though they seemingly aren't interested in the victory right now. Your husband needs time to heal and your children need to back off and accept the consequences for a while. Don't fight with your husband to "let it go" and don't encourage your son to keep apologizing. Actions speak louder than words and the best thing that your son and/or daughter can do is to begin to show their step-dad that they love him without opening the wound each time. One of the hardest things for humans to do is to just let sleeping dogs lie and move on, it's the one that that animals definitely do better than us!
If your husband and yourself have a strong relationship, it will survive this, technically it's only 2 more years before you have the house to yourselves. Celebrate each other, and at the same don't neglect your son.
The truth of the matter is that your son already has a father and he doesn't really need another one it seems from your post, so whether or not he accepts your current husband as a father figure or not and vice-versa at this age doesn't matter much. The worst thing you could do to your marriage at this point is try to fix this situation, it will just create a greater divide between you and your husband and remember that is initially what your children were driving at. If you do try to fix the situation, it may seem like you are on the childrens side of this, not a good idea as it might create an even bigger rift...and truly counseling is not a bad idea. For you and your husband first and MAYBE include your children later. Your husband needs to know that he is MOST important.
I disagree with the other posters who say that your children are MOST important. If they were younger children, then yes it would be most beneficial to work this out for them, but what I have learned from my own experience is that making sure I am happy, rubs off on the children. And making decisions for my childrens sake has usually back fired. Making decisions that are best for me, tend to work out better in the long run. This is your life and soon...2 years or less your son will begin his life, don't let his mistakes destroy or defer your happiness anylonger. But at the same time you still have to be his mother.
At the end of the day...just give it time and try to stay out of the line of fire. You'll thank yourself for it at your 10th and Silver or Gold anniversary!
Good Luck and hope it all works out for the best for you!