This may seem harsh and judgmental but maybe that is the exact clarity you need.
I am confused how you can be completely baffled by his actions.
You betrayed and abandoned your husband, the father of your children...
You came to the decision to do this in less then 2 months...
You know he has already suffered betrayal from one wife...
You know that he knows you lie excessively...
What are you expecting, a white picket fence dream marriage?
There is a very old saying that has proven true time and time again...
We reap what we sow.
This must be a difficult time for you. I would like to start off by telling you that I am not trying to offend you. Some of this may sound harsh, but everything about infidelity is harsh.
First of all, the internet is a horrible way to meet someone. When you take into account that you were lying to him, he was lying to you... the relationship was based on lies from the get go. The internet allows so much anonymity... you can't see the other person, you can't hear the tone of their voice, you can't see their expressions and when you add all of that together, you really don't know who you're dealing with. In essence, you get caught up with YOUR IDEA of that person and not the real person.
PTSD may be the real issue here, or it may be a combination of the PTSD, infidelity and all of the lies. Unfortunately, there are no easy answers for PTSD or the infidelity.
I ruined a good portion of my life because of infidelity and PTSD.
PTSD breaks a persons will to continue they become broken and it stays with me for nineteen years now and seems to keep coming back idk what to say other than he might come back to you im not sure :)