I'm a man and have been to Thailand maybe 15 times, but not for the sex industry. It is a beautiful place, and I thoroughly recommend going to anyone. There is so much to do, and it is one of my favourite places.
That being said, I do agree with everyone above that 95% of men/groups of men ARE going for sex. It's actually amusing (cringy) to watch at the airport... all other flights have families, businessmen, old couples, etc, all in 'normal' ratios, but with Thai flights, there is a wildly disproportionate number of single (sleezy-looking) men.
For a girlfriend/wife, I'd say it's a dangerous place; not for safety, but for relationships. I've been there with family mostly, but also with my partner, and all times I've been approached by women, even in completely innocuous places. I'm not going to lie, it's great for the ego, but also incredibly disturbing as those girls look young!
There's no way at least one, if not all guys are going for that reason.