I can't help in the way of light placement and strength of the strobes, as I generally use natural light for most of my portraits, but I did notice, like the others, that they're really hot on their left side.
We've lost detail in the whites and the drop off is much too harsh on their right sides.
I would bump the contrast up a tad, too. Your conversion looks a little flat.
I did a quick edit (your file was small, so I did what I could with what I had).
I just selectively lightened their right sides
bumped the contrast
brought back a little detail in their shirts
gave their eyes a little kick
cloned out some stray hairs and all of the pesky lens dust
and warmed up the BW conversion (this was personal choice, as I am more partial to warm BW's)
Your couple looks really relaxed and comfortable in front of you and your camera