Many internet sights can accomodate you. You should have no issue in SD
One of the evening news shows did a story about men on the DL and frequently men on the DL are incredibly anonymous and frequently do not practice safe sex as they don't want to be caught buying stuff that they otherwise wouldn't need for their marriage. A lot of unsafe sex happens which then gets brought back to their wives. One of the stories focussed on a group of guys on the DL. One of whom had a baby who was born with some conditions, and it was uncovered then that the baby was born HIV Positive through the mother. Guess who else was, the father. He came clean about his life on the DL and told the guys he fucked around with, all of whom were married, all of whom were HIV Positive and didn't know it. So if that doesn't scare you to rethink life on the DL, please please please be safe.
The author wrote something about losing something if he got caught. That is a rough place to be. I get it. What I think is worse is living a life that is dishonest to others and to yourself and I feel at that point is when you really lose something... yourself!
I think that the part of cheating that really irritates me is not the infidelity part but putting your spouse/partner at risk. When I hear that a straight guy got a mistress pregnant the first thing that comes to mind -- he had unprotected sex? So for the love of God, please be safe.