I'm in the same boat. It's shit.
I lost my DH to Motor Neurone Disease in March of this year. Only diagnosed in summer 2025 too, so we didn't have long.
Since he died I became eligible for death in service benefit, return of some pension accounts (reinvested into another pension for me) income from his private pension (widow's portion) and a payout from his life insurance to pay off the mortgage. So I am now fully mortgage free with an income. Sounds great on the face of it, doesn't it.
Like you, I'd give it all back tomorrow if it would bring him back. He never got any retirement. None of our plans we were actually saving for came to fruition. It's just so sad and unfair.
I've got the money invested to give me enough income, and so that it can't be frittered away. I'm doing everything I know he would hope I would with it and I am so relieved and grateful for his/our fairly astute financial planning, without which I would be sunk really. It feels awful though.
Everything was thrown into further disarray by the death of my elderly mother just three months after DH. So my sibling and I are now also dealing with her estate.
In fact, I will be dealing with 2026 and its aftermath for a long time to come, I think.
I know my DH and my mother would both have wanted me to be secure and to enjoy the money, and I will, but it takes time to settle down and I will always miss both of them.
I am sure your DH would want the same for you, but I do understand how it feels. Very much so. I find myself sitting in my living room late at night within sight of his urn having imaginary conversations with him in my head.