I met/ chatted to a 'gent' 15 years ago at a swingers club, who ended up inside for 5 years and had only been out for 12 months or so when I met him. He was a CD/ sissy and was one of the leaders 'bitch/gf' for that whole 5 years. He said it was the only way he was going to survive the whole sentence without being repeatedly beaten and raped. You're correct as far as him trying to look feminine the whole time (best he could) but the gang leader/ bf was very protective of 'her' and 'she' rarely had to have sex with other inmates. But as you said, he did have to do chores, clean etc. and obviously supply him with all the daily sex he desired, but they actually became quite close and sort of loved each other in the end he said. The bf would always get her lingerie/ perfume/ razors/ make up etc.... but also chocolates, cd's. dvd's.
But he did say, if it wasn't for being able to act/ pull off a willing genuine sissy role, he would have never got out of there alive. Before he went in, he said he was at best bi-curious, by the time he was out, he only identified as transgender and was quite happy that way. It was a fascinating conversation and was amazed the life he lived inside as well as being a 'willing' sex slave.