OP I’m in a somewhat similar situation and I can understand the muddle. So my thoughts probably won’t be very coherent either. first off, totally agree mat leave debt should be shared.
unlike some I do think the money is significant. It is only fair and sensible if one person is bringing in much more money and paying more expenses and working harder outside the home, the other should be doing more inside the home. So one thing you can do is simply start paying less and having him step up. I have actually never found the idea of splitting by income fair. I think each party should benefit equally from living together…. Or, each party should have the same disposable at the end of the month. You are overpaying if you have less at the end of the month than he does. That is blatantly unfair, and I would simply adjust that, reducing your payments as a starter by half of the amount he is saving each month.
Even with that, he should be contributing more to other things, as you will be contributing more financially still. This speaks to a deep sense of equity within us.
Now that can be practical and mental - and should be if he has more time. But it can also be emotional.
I talk with my DH about tank fillers. I have a tank internally, and when it gets depleted - because I’m doing too much, holding too much up, working too hard for others, supporting others too much financially and emotionally…. I get depleted and resentful. He knows that part of his role generally as a good partner, but ESPECiALLY when I am carrying more of the load, is for him to fill my tank. He literally has a list of tank fillers in an email from me. They are all about me receiving and feeling looked after and nurtured. Him running a bath for me, bringing me flowers unexpectedly, making a batch cook of the one thing he makes really well, giving me a long, ‘receive only’ sensual massage, etc etc. If I get more nurturing in these ways, I can live with being the provider. Because my life is better for having him there, just as his is for having me. The problem again is equity - if his life is way better and easier for having you, while yours is…. Not way better and easier for having him. That is wrong.
Also very important to me is seeing him work very hard, as I do. Yes, he’s a creative so earns less automaticallly than I do. But that shouldn’t equate to sitting around doing nothing. I’m fortunate my DH works very hard- and I have huge respect for his creativity. What he does matters in the world and will likely live beyond most things I have done. so no it doesn’t bring the income (though it is possible it results in big payouts at specific points). But he’s not lounging on the sofa.
on top of this, he is physically hyper masculine, so I DO absolutely have that feeling of being looked after…. He barely lets me lift a shopping bag, and when I am tired I lie on his chest, and feel recharged. And if ever I was physically threatened, he would 1000% be my defender to the death if need be. Literally.
While we are meant to live in this post modern world when women and men are meant to want and need the exact same things and be equally happy to be the provider…. I do think that sense of having a protector is important - especially if you are stepping up in so many other ways.
You mention your sex life…. Very common for many long relationships, but honestly not unrelated, I would guess to your predicament. Men who are not pulling their weight, and can’t claim to be the man of the house through earnings etc either…. It’s not great for the dynamic in bed often and their sex drive. Not a problem for me in this marriage but it was in my last. I carried all the weight in that one, and earned more…. Did everything…. And at the age of 40, he left me for a twenty three year old….. someone he could feel the big man around. Not saying that will happen to you…. But if the potency/ effectiveness/labour/earnings/physical drive are all in favour of you…. It’s a tough balance for either of you to sustain without resentment.