Trying to start over with an ex-fiance

This time last year I was planning a wedding with a man I had been dating for almost 7 years. Throughout our time together our relationship endured lies, cheating and break-ups. As the relationship evolved things between us gradually got better and better. He proposed to me and immediately I was nervous. Excited but nervous. We never really dealt with our issues from the past, we simply ignored them. Needless to say, because of our disregard to those issues I did not feel comfortable with moving forward with marriage. I ended the engagement He was devastated. I moved out and moved on instead of being open minded to counseling. There are no words to say how horribly this effected him.
We hadn't spoke for nearly a year except for his occasional texts or phone calls asking me out for drinks or dinner. I spent the last year working hard to become the best possible version of myself and he has been working with a counselor to become the best version of himself. We recently reconnected at a local event where he asked me to dinner. I said yes. We have both agreed that after some much-needed soul searching we may be able to slowly give this another try. Counseling is obviously a must. However, he still has a lot of animosity towards me for ending the engagement. He is guarded and mistrusting of me to not to break his heart again. He is demanding that I convince him I will not leave again when things get hard. If we commit to this relationship again, neither one of us wants to go through another failed engagement. In my mind his feelings are justified and I am sensitive to that. How can we break down this wall of mistrust and move forward? What can I do to gain his trust back? Are there relationship exercises we can be working on to help with this issue? Counseling will help but he is not quite ready for that. How do you move forward?

I've been in a pretty similar situation myself and I'm still working things out with my boyfriend, but things a going better and better. I think that you should both communicate a lot and express your feelings, if he's scared you'll leave him again, show him how much you love him. I you stay open with him, you will win his trust back. But keep in mind that regaining someone's trust is a slow process, if you really want to work things out with him, you should give him the time to feel comfortable again and don't pressure him. I also think you should talk about the problems you ignored because ignoring problems in a relationship usually lead to more problems.. Unless you've both moved on on those, if you did, you could leave them in the past. But if something is still bothering you, you should definitely talk about it.

Remember, communication is key!

Now I don't know any relationships exercises.. But I really hope I helped you.. Good luck!