I don't have a sexual relationship with my dp.
I think maybe your dw was floored because it was the first time it had been mentioned. She has made assumptions about what you are feeling and she was actually very far off about how you.
So now you have got it out there, I reckon you should consider it as conversation number 1 in a series of ongoing conversations. As long as you are not too whiny, keep it calm and talk about it in the right way, I think you should consider it an unfinished topic, and schedule a time together to have conversation number 2. Don't let it blow up into a big emotional argument.
I am no sex therapist, but If it were me, and my dp said what you have said, I would make a BIG effort (actually I would be delighted he had said something). Maybe she will too? In my case it may be too late.
For our part, we are sexless but we haven't talked about it. I was hurt initially, wished for more sexual activity,, but now I don't think I have much of a libido anymore so don't mind. It has been so long that I am not sure I can get back on that horse anymore, so to speak.
I am not staying with him for the kids and I don't want another man, I am happy as I am, but yes I would say we are coparents/house sharers. I am happy sharing a bed with him, I like chilling with him and going out with him. I don't feel sexually frustrated often, if I get horny I have a dildo which is fine....
...however, writing this has made me think that I need to follow your lead and talk to him so that I am not making the same assumptions as your wife seems to have.
Keep talking to her, find out what she is feeling and if she thinks she can change at all. See if you can find a compromise, keep it kind and calm, keep the love and respect to the foreground. As I said, if my dp approached things right, I would make big efforts to try and bring the sexiness back.