Hi there hat18,
The timeline for healing is pretty long. As foreverlabeled mentioned, 2-5 years is about normal. When I first came here and read that I was pretty sure that my BS and I would be different. Nope. It was more like 6 years and there are still times that he triggers.
Rather than focusing on trying to find a way to "move on", a better strategy is to work on yourself, in two ways.
1) Figure out how and why you were able to betray your BS. You mention marriage counselling but not individual counselling for you. You mention you and him discussing reasons for your cheating, might I inquire what those were?
2) Develop some tools for dealing with difficult feelings without having to shut them down or getting carried off by them. A lot of times when my BS was hurting my apologies were really a way to try to short circuit and shut down his expression of pain. Sometimes I tried to talk him out his feelings, sometimes I tried to tell him he no longer had any reason to feel that way. Sometimes I made it about me and how horrible I was that I had done this to him and how awful it made me feel. None of that helped.
What did help was the realization that he didn't want to feel this way, and telling him that I knew that. The apologies that helped were very specific rather than general. Keeping my defenses low and my curiosity high about what he was going through helped.
A mindfulness practice that had daily meditation practice as its foundation was a big help for me. Journaling and counseling also as it gave me a place to let me frustration flag fly. I have a lot of pages in my journal with just the words "FUCK THIS FUCK THIS" scrawled across in large letters. Saying it there meant I didn't say it to him.
If you haven't yet had a chance, I'd like to encourage you to read "How to Help Your Spouse Heal from Your Affair" by Linda MacDonald. Also, the post "Things Every WS Should know" by HUFI-PUFI on this board. I'll bump it up to the top for you.
I know the timeline seems daunting. I know what you are both going through is painful. Try to remember that infidelity imparts a psychic wound of trauma to the betrayed. If he'd had a major accident or a stroke, something that wasn't your fault, and he was still struggling with recovery at 18 months out, would you be thinking as you are now? Trauma has to be processed. It takes time and often requires professional help. I don't know if he's in IC but if not perhaps it's something you can bring up in MC.
Proceed with conviction and valor.