all three lead to him declaring "Now let's get to the intimate part".
And what are your choices at
that point? Unfortunately I don't have a save, I can't go check. I remember eventually being able to turn your face away when it seems like he might go in for a kiss.
That's the point - there are no choices. It is a declaration, not a suggestion, your character has nothing to say to it. Then you dance intimately, get to the kissing position - and THEN you can turn away (or kiss him).
Don't get me wrong! I personally have nothing against the whole thing. Wyll is hitting on Lae'zel and SH, why should he ignore my girl? Even though dancing was very sudden without any premise, it still can be seen as a sort of extended variation of that "hitting on" banter. As if he knows about Astarion, but wants nevertheless check his chances. For me, it's all good and even if a bug with flags, it's fitting and adds replayability.
But it does not make the scene clear or even coherent. With Gale Larian finally marked the border: here is a friendly conversation and past this point - romance. With Wyll they did not do it (yet?). You simply dance and then, without any input from your side, suddenly about to kiss Wyll. You can reject the final step, but this is not what I would call "just say no". Before his declaration, two options have to be added similar to Gale's, like "Well, that was fun, I'll go now" and something about
you willing to get intimate.
A very simple fix (though I suspect his reaction will be similar to Gale's, as if you rejected him with prejudice).
