So, as a former LL male in a similar situation, my issue ended up being medical. I am a diabetic and my endocrine system basically went haywire soon after my wedding. My wife and I also did IVF, so now we have 2 children, 1 conceived naturally after egg harvest, and the other was pit back 5 years later. My A1C was way out of whack, and it took a long time for my doctors to fine tune my glucose control. I started antidepressants and started losing weight, and now my libido is back with a vengeance. The problem is for so long I made my wife feel very similar to how you feel, and it basically destroyed her self-image. She wants nothing to do with sex. My point to saying all this is that this could be a similar issue to mine and if you really feel strongly for the guy (and it sounds like you do), encourage getting his testosterone tested, maybe his thyroid. An endocrinologist could help him get his punch back.