lisalisa if you are his lawyer you ought to be able to ask him why he didn't instruct you for a particular piece of work, rather than just stewing about it? I think by doing that you are making it into a huge big deal which it may not be.
I'm not a lawyer as you know, but certainly if I found out a client, particularly one I'd been so friendly with for such a long time, had gone elsewhere for something I feel I could have helped with, I would ask. DH is a lawyer, as you also know, and I know he'd do the same.
I'd have a meeting and say I wanted to review how things were going and address it. There may be a good reason. There may not be. But at least you'll know, and if it's a performance/quality issue, you can discuss addressing it. I don't think you need to walk away from him completely without at least finding out what the issue is and seeing if it's something you can sort out together. For your own peace of mind if anything.
Hope you get it sorted.