Hello bellarosie and welcome.
You're right, you do have to find a whole new way of living and nothing and no one, can every truly fill the hole left behind by an adored partner.
I agree with GrandmainOz that you could tell your son and his wife how you are feeling.
It isn't burdening them, it's including them, as they wish to be included in your life. And they do, obviously, because you all get on so well.
It really is awkward, even when it's your Mum, to know what to say for the best, when something so terrible happens, so please, trust them with this and make the first move.
You could say, 'I feel so lost now and I am so very grateful for your help and love, it has made a world of difference since my beloved passed away.' And take it from there.
My son, like yours, has always been very close and still is. Never comes here without hugging me as soon as he walks in the door and always before he leaves. He would, I know, drop anything, however important if I needed him but like you, I hesitate to ask....unless it is absolutely vital.
In this case, dear bellarosie it is vital; you need the love and compassion of your son and daughter in law to help you over this awful time. Don't deny them the chance to give it.
What were the first ever records that you bought and when?
Parents-in-Law. What do/did you call them?