is this cheating?

A few months ago, my husband and I were in a rough place. Literally screaming at eachother everynight, divorce getting brought up multiple times a day, etc. One day on his way home from work, he called his old bestfriend who sexually assaulted me a few years back. He then had his little brother get a girls number that he used to go to highschool with. He has not talked to this girl for about 3 years. He called her, told her he wasnt happy with me, that he was sorry, he wished he was still with her. She told him off, so he blocked her number. I found her number a week later and texted it just trying to figure out who it was as it was saved under the name "dave" she then explained everything and he admitted to it. 
Fast forward to now: We have sought out counseling, and we have not fought in quite a while. We have been doing good and he has been working to get my trust back, he no longer takes his phone to work and im allowed to go through it when ever i want. I was pregnant at the time when he did this, we ended up losing our baby. Doctors said the amount of stress i was under caused my hematoma to bleed more which caused my early labor, and her not surviving. 
Yesterday we were driving to the funeral home to pick up our daughters ashes and his dad calls. He says how his mother is telling everyone about when he called that girl and saying it was my fault, im a horrible person, etc. Of course I get upset. I mean come on! Im on my way to pick up my daughter from a funeral home and im being told im a horrible person by a woman i dont talk to? He got off the phone and was telling me to ignore her and that im an amazing wife. 
Then it gets brought up about what he did. He then tells me "I know we have different views but i didnt cheat on you. It was wrong but i did not cheat" 
To me, he did more than cheat. He completely shattered my heart and trust. We lost our baby. I feel as if all this progress was for nothing because he's still thinking he didnt cheat. 
So my question is, was what he did cheating? 
(Sorry this is long, i wanted to post the whole story and get my venting out as well)
Update: we were NOT broken up. We were not getting a divorce. It got brought up alot but we always fought for eachother to stay together even when we werent happy. The day that he did it, before he went to work he told me how much he loved me, didnt want to lose me, and for once, i had hope. We had planned to go on a romantic date that night as well.