First off, I am sorry you are going through this! It really is hard. let's sit back and think about this. The two of you fell in love, married and had children right out of high school. Though there is absolutely no excuse or right in infidelity, your partner may be going through a time in his life where he is yearning to break out and experience the "normal" manly sexual ventures.
There are several reasons men cheat. None of which makes them right or justifies them.
Lack of sexual pleasure
Some men have an increase of hormones during these times and because they are "men" they do things they should not do to deal with it. We, as women, cry or talk with our girlfriends. Men do not do this.
It sounds to me like the two of you have several things going on in your relationship. Though they are wonderful things, such as your business, children, a home, etc. They are also very stressful things that take a huge responsibility and commitment.
There are a few things I want to ask you and a few things I am going to suggest. Sometimes counseling is not enough. How long have you been going to counseling and what were the reason you began? Do you both attend as a couple or do separate therapy? Have the two of you talked about the struggles you have and what have you tried, other than counseling to fix them? What does he say about his infidelity? Are the two of you happy intimacy wise? How is your dating life together, I am assuming it is difficult due to children?
I really need the answers to these questions in order to be more accurate, but a couple of things to try.
First, sit back and relax when you get a chance. Take this time to really find your inner peace. When your children are sleeping, clear your mind and feelings and really think about what you want out of this relationship and what is realistic. We all want the perfect love and life, but it is not realistic.
Second, try to take some space from calling your partner. One thing you need to understand about men is that they do not like feeling pressured or controlled. Give him some space to think about what has happened and what the current situation is looking like. Do not be so quick to move forward. Try to let him do the calling and allow him to talk about what he wants to talk about. Give short and simple answers. This way, you are allowing him to initiate the conversation and feel as though he is in control. Why is this important? Because a man who is feeling pressured or guilty, will shut down and not talk.
What you need right now, is for him to initiate the conversation which will allow him to say what is really on his mind and in his heart without you leading it out. Also, you do not want him to think that you are always so forgiving and will always allow him to talk his way back into working things out.
Finally, I would suggest that you do not move forward at this time. Moving back in with one another and going on like nothing has happened will not work. You will be in the same place months from now if not worse. He needs to realize what he has done, why he has done it and how to fix it for good.
Some men never stop cheating. Others just need more help than some. If he has always cheated, he may have deep issues that have been unresolved. Maybe a cheating father, abuse as a child, trauma, broken home?
Another thing too, is quality time with one another is very important. You both live a very, very busy life with a lot of responsibility. You also have two children. This makes for very little time with one another. I always suggest that my clients have a date night at least once a month, no exceptions. Make this time a time to NOT talk about past, issues, work, kids, etc. Only enjoy the date night. It truly makes a difference.
For now, answer my questions so I can get an idea of the bigger picture and try some of my suggestions in the meantime, you benefit from a coaching call with me. If you are interested in that, let me know and I will provide you with the information to reach me.