Not all actually. A woman I was with at the weekend wanted to see me do it and also an ex-gf did.
Plus the fact you see women on here liking "cum tributes".
I'd say maybe it's a 70/30 thing.
I've been with women who have wanted to see me wank and cum and then on another meet wanked me off to make me cum and see it spurt... but hey we are all different