Having been down this road with both PTSD and a divorce, as well as seeing many others deal with the same during my years of service, I can say without question one of the most difficult things life can throw at someone. Others have said it and I will echo what they have stated, you have to be happy in your own skin before someone else can be happy with you. I learned in my Army training that it tales a "Significant Emotional Event" to change your core personality and the breakup of a relationship is a SEE for sure.
You both did not fall in love overnight and you are not going to fix this in a day or two either. Try to reflect on all the things you both did and places you went when you were courting her and make an attempt to recreate some of those experiences. Send her flowers, leave notes that tell her what she means to you in places she will find them. Often easier to write out you feel than it is to speak the words. Maybe get someone to care for the kids and get away and spend some alone time together.
Words often cause more harm than blows, so always try to temper what you say and avoid speaking in anger or when emotions or high. Never assume she knows how you feel about her, tell her how much you love her and what she means to you. Try to make each day better than the last and please don't forget to love the kids during this tough time.
Walking a Christian lifestyle and living in the light of the Lord is always a smart way to lead your life as others have also mentioned.
Lastly I will speak to my own divorce, I neglected, and took her for granted for so long that allowed another man to enter the picture and fill those emotional and physical needs she was not getting from me. You stated that she was out of town and that throws up a red flag, trying to figure out if another is in the picture without being accusatory is a delicate subject, but not loving you is one thing, being in love with another is a much harder hurdle to overcome.
Please remember your children need you both and never chose a long term solution, to a temporary issue.
There is a song that goes,,, Thank God for unanswered prayers,,, I'm so much a better man because of the changes I made in my life because of my divorce and the woman I have now been married to for almost 25 years has been a blessing.
Stay strong and surround yourself with positive people.
God Bless my Brother
Steve