The redhead

I guess I'll be the token male on this thread!
I'm not single, however, but I encouraged my girlfriend to get the surgery once she'd made up her mind (and once I was convinced that it's safe). Not just for the obvious, "noble" reasons -- it's good for her health, she'll live a longer, happier life, etc. But also for one very un-noble, "selfish" reason as well: I wanted a skinnier girlfriend.
Mock me if you'd like, but let's be honest. Men -- especially single men -- are visual creatures. We care, very much, what you look like (even when we protest that it doesn't matter, it matters). Hopefully, if we're good guys, that's not all we care about, but it's pretty important.
So, I can't speak for other men, but I can speak for myself, and I bet I speak for a lot of men. Mostly -- at least in the "first impressions" department -- we care that a woman is healthy, and looks good. This surgery achieves both of those goals. Sure, you may not want to give him every gory detail, but that kinda goes without saying (a new relationship isn't usually the place for detailed talks about former medical procedures). If you need to explain anything (for instance why you eat so little, or why you can't have carbonation), just explain that you had stomach surgery in the past, and it's doctor's orders. Most men really won't care beyond that, as long as you're healthy.
But honestly? I think a guy will just be thrilled to be with a "skinny" girlfriend, to the point where he doesn't really care HOW she got skinny.
In the long run, hopefully, we'll move beyond caring so much about appearances. But the truth is that we NEVER get completely past it; we always care at least a bit what you look like (which is why the sleeve is such a great thing for relationships!). Once we start moving beyond first impressions/lust, we should just be thrilled that the surgery is making YOU happy, and less judgmental about it. In other words, as the immediate visual draw becomes less important, our caring for you should take over, and in that department lap sleeve is a plus, too.
There will likely be a small percentage of exceptions, but honestly I think most will be happier with the results and not care how you got there. The exceptions who will make a fuss about it, aren't worth your time.