"Lets turn it around for a moment. You blow your load and she wants to keep going. How does that make you feel?"
That's actually a very good way of looking at it. Most guys are completely sated after they cum. It's not like it wouldn't still feel good as much as there is just a total lack of desire for more sex at that time.
For me though it's like, "Damn, now I have to wait another 5 to 10 mins to recover". That is why the Mrs is more than happy to say, "Go play, so I have some chance of actually being able to sleep later tonight" ;-) If the OP is like me, it could well be his wife thinks like mine.
If both parties are getting what they want out of the LS, it's all good. I do truly love seeing the Mrs have a great time, so I have no reason to believe that she wouldn't enjoy seeing/hearing me do the same.

