Making a blended family work is very hard. been there done that. Both wife and I had to let go of "you're blind to your kid's faults and always picking on my kids". We very nearly divorced over it. And our difficult child's used it against us, both my daughter and hers, to the hilt. (My bio daughter went to live with my ex, who's a difficult child herself, but that's another story.) Family counseling turned out to be very helpful, although oddly it seemed at the time to be making things worse, not better... one therapist fired us, told us she'd had it, go get a divorce already! But the lessons did take root and mature in time. Now both of us are keenly aware and can spot being played off against one another a mile away. If anything, tend to make excuses for the other's kids and be harder on our own. Really, we both consider the kids "our" kids now, and difficult child even wrote me a letter saying that she could now appreciate how I accepted her as my own daughter even when she rejected me.
I don't know your situation but it does seem to me that perhaps a family counselor in a mediating role could help. One of our issues was that we would use that same kind of all-or-nothing "you think my kid is worthless and yours is a saint" language, and we had to both learn to moderate and not be so accusatory. We were taught not to say "you do such and such" but rather "I feel like I am not able to talk to you about such and such without you becoming defensive." By putting it back on yourself, that you are trying to understand and work through rather than confront and accuse, you might not trigger the defensive reaction. Your husband, for his part, is going to have to recognize how he enables the boys to try to drive a wedge between you. Maybe a neutral party could help open his eyes.
Your family is in my prayers.
