DMSO is fantastic stuff in terms of effectiveness, but my bet is that your SO will neglect you for a day or two when you do. Not matter how pure you make the stuff, as soon as it reacts with your body it will start to smell less than good. It’s not just a matter of purity, but more the chemical reaction that makes it so effective.
I’ve got a couple of bottles here that if I could be sure I wouldn’t see anyone for a week or so, I’d use it in excess every day. In itself it is very useful, with additives it’s even better. If you consider flying ants to be a bad thing, it’s pretty much the opposite of that, but still bad. MSM is a poor second cousin, but without any of the sides.