Much better when they're young. Adaptable and able to accept change before adolescence bulldozes in. Getting them settled in their new normal before that happens is wise.
I bet you are in peri. Your 'like me like me aren't I pretty have babies with me' hormones are beginning to drop and the 'what the actual fuck is this?' hormones (that were there all along) are being revealed. Your inclination and ability to put up with shituations will plummet further.
We're supposed to like, love, respect, fancy, enjoy being with our partners. That is the point. When they consistently fail to do anything that might help that, and persistently do things instead that disappoint, offend and repulse - we have a problem. And when they announce that expecting anything else is unreasonable and too much, then the relationship is toast.
If this was your house to begin with, bear in mind that as your husband co owns it.
He will probably do the demanding 5050 thing as a 'control you / get out of child maintenance' thing.
See a solicitor. Find out both your rights and responsibilities. Where you stand. Knowledge is essential.
Right now you are presenting your sons with a role model, a blueprint for how to behave towards women. What a wife is worth. What relationships are.
You could present them instead with an example of how women can and do say 'no, not having it and am not inflicting it on the kids.'