It sounds like he needs therapy and counseling of his own to help him through your difficult time.
It's good that you're getting therapy, and that you're trying to get better. However you need to really doing all of that for you, not because you want to save your relationship.
You've been through something traumatic, and this is your time to ask others for help and support. For you to take the time and put in the effort to recover from it.
If people knew up front the real trauma and tribulations they would have to deal with in marriage... Most people would never go through with it. He gets to see that up front, and he's concerned. Rightfully so.
It doesn't get better than when you're dating. So if it's difficult now, it will be more difficult when you're married.
I'm sorry if this isn't what you want to hear, but it sounds like you're having a rough time and not doing the things that you need to do for you to be OK with your life and recover from what happened.
He's giving you the chance to do that without killing the relationship. Maybe you should take it.
"Well, then," the Cat went on, "you see a dog growls when it's angry, and wags its tail when it's pleased. Now I growl when I'm pleased, and wag my tail when I'm angry. Therefore I'm mad."