I think that we need to make a distinction here between not needing to say 'yes' to sex in a 10 year marriage and - as happened in this case - saying no to sex in a 10 year marriage.
They are poles apart.
I am with my dh and partner for 12 years. There is no verbal negotiation of consent in our sexual relationship: we understand eachother nonverbally if it's a yes, a kiss leads to more, to cuddles and desire etc. If one of us makes an advance the other doesn't wish to reciprocate, then it is verbal: from a straightforward 'no' to the jokey 'get your mitts off me, I'm tired' kind of response that Anchor gave.
I can understand why people are confused about the issue of explicit consent in a marriage e.g. in some posts it does seem as though this is a formal part of 'proceedings' e.g. "do you, my lovely wife, consent to have me putting my penis inside you tonight?" - and of course, this seems unnatural and strange.
I also understand that many women sometimes have sex because they feel they should. The ebb and flow of sexual desire over a lifetime means sometimes one partner is not really 'up for it' but knows, somewhere inside, they will enjoy it when it happens and besides, they enjoy the feeling of satisfying their partner even if they themselves are not particularly interested. This is not always a sexual thing, per se. I seem to spend my life asking my husband for neck and shoulder massages and I know that he finds it tiring but he does it because it makes me happy. And sometimes he says no and I say 'ah go on! Pleeeeeeeeeeeease!' and he does it half-heartedly etc etc. There is an element of give and take about personal desires (sexual and non-sexual) in any relationship.
However, what happened in Anchor's case is that the natural give-and-take of a long-term relationship, all those little compromises of personal desire we make for one another etc, was violated. Because, on this occasion, the 'ah go on! Pleeeeeeeeeeeeeeeeeeeease' was met with a no and a firm one in that - verbally and nonverbally as she went back to sleep - and her husband, instead of continuing the interaction on an equal level, chose to override the rejection. He essentially said, to hell with you saying no, this is what I want and I'm having it whether you want it or not. Perhaps he told himself he wasn't, but he chose to have sex with his wife when she had said no and she was, essentially, asleep.
I can't see how anyone can spin that as being okay and not a serious violation of trust and love in Anchor's relationship. No, it is possibly not the same as him beating her down and giving her a black eye while doing it in the sense it was not, maybe, intended as an act of violence, but it is absolutely and utterly NOT OKAY and it was an abuse of power and demonstrative of a pervasive attitude in society (as demonstrated on this thread) that marriage = an available vagina, regardless of the woman's feelings about that. It was sex against Anchor's consent. And that, I'm afraid, is rape.