Unfortunatly this is not the issue.
What you just mentioned is perfectly covered by No means no.
Someone makes a move, the other person says no, if he keeps insisting it's sexual abuse/rape. Simple.
Affirmative Consent on the other hand is a lot more obscure.
It's more along these lines.
Person wants to make a move because he thinks he is getting the right signals. Makes a move, doesn't get any negative feedback. (The move could be anything, a kiss, placing of the hands in x or y place, penetration etc.) To only way to avoid this is, to literally ask for permission constantly for everything you do. Which is a silly concept.
But let's assume that consent was asked and was given (clearly and vocally expressed, as that is a requirement here as well). But the day after for XYZ reasons the one of the participants retroactively decides that while in the heath of the moment action xyz was okay, not it isn't. (I'm not even assuming malicious intent, which is also a factor).
Now this has to be arbitrated. In arbitration all this comes down to Word against Word. Affirmative Consent is not demonstrable, unless you literally filmed said consent being given.
The problem with Affirmative Consent is that it is EXTREMELY VAGUE, and removes EVERY SINGLE PROTECTION granted to someone being accused. Essentially the person being accused has no rights. This is silly.
Again, this would go into the realm of whether people lie about rape or not (I'M INTENTIONALLY AVOIDING GENDERS, BECAUSE THIS IS NOT ABOUT GENDERS, tho in practice it hilariously reinforces gender roles, by typically assigning the victim role to women, and the aggressor role to the male, and thus reinforcing the idea that women lack agency), and there the fact remains that people are essentially people, which means faulty. There could be a bazillion reasons why we mishandle sexual assault cases, mental illness, inability to understand consequences, malicious intent, mistakes, decisions driven by preconceptions or religious norms and so on.
We as a society are experiencing a rape hysteria. It's not dissimilar from the Satanist Child Abuse Hysteria of the 90's,
https://en.wikipedia.org/wiki/Satanic_ritual_abuse perhaps simply this being larger in scale and scope, and perhaps being a bit more grounded in reality. But it is still a hysteria, and we are still overreacting to it, as we did in the past. Driven by a media frenzy (add social media to it today) and honest good intentions to address a perceived problem (in this case I'm not saying the problem doesn't exist, I'm saying we are overreacting).
We can't throw logic and reason out the window in a frenzy to address a problem, real or perceived. On the contrary we should be applying reason, logic and an analytical approach to finding a solution.