Do couples always agree consent in verbal terms before they have sex? Of course not, because established couples have non-verbal means of establishing consent both before and continuously throughout sex. You just know.
If a couple don't have the trust and ease of communication to be sure about consent, then the person making the running needs to establish consent clearly and hence probably verbally. When there are borderline cases - I think we are at the 'just do it' stage but I'm not sure - then the risk is borne by the person making the advances.
Some commentators talk as if it is intolerable for any risk of getting it wrong to be put onto men at all: all the risk has to go onto women. If a woman doesn't say no men are allowed to assume that means yes. Even if she is unconscious. What utter rot.
A verbal consent is not enough, of course, if it is obtained with threats of any kind. But just establishing the requirement to get consent is a step in the right direction.