What your husband is going through is absolutely normal.
Death is hard enough as it is. No one wants to have the thought of their loved one dying and ending up in a dumpster for God's sake.
Your husband needs to continue talking with your pastor and get grief counseling. The people who handled the cremation can give you references.
It makes perfect sense to me that this is all coming out nearing the anniversary of his dad's death.
I urge you to google "the 7 stages of grief". It might help you to understand what your husband is going through. Guilt and blame are one of the stages.
It might take some time, but he can work through this with help, including yours.
He said it himself, he's been holding things in for a year. He might as well get it all out and go through the stages until he can find acceptance and move on.
I used to work in the counseling office at a cemetery and I've seen this a thousand times. He's not deliberately being mean to you.
Yes, planting a tree or having a stone of some kind would be lovely, but this may or may not be the right time to do that. He may be all for it, and then again he might not be ready. And that's okay. His emotions are very raw right now.
If your husband won't see a grief counselor, you can still see one. I can guarantee they will tell you that blaming....somebody, anybody, (although not a happy thing when you're on the end of it) is actually quite normal. He may even pile guilt on top of guilt for blaming you.
Depression can also be one of the stages so you want to watch out for that.
I'm really sorry all this has happened.
I believe you can both work through it though.
Best wishes.