In Arkansas, "mentally defective" means:
" (4) (A) "Mentally defective" means that a person suffers from a mental disease or defect that renders the person:
(i) Incapable of understanding the nature and consequences of a sexual act; or
(ii) Unaware a sexual act is occurring.
(B) A determination that a person is mentally defective shall not be based solely on the person's intelligence quotient"
-----
So, no, I really don't want my "loving husband" having sex with me if I suddenly develop a mental disease that makes me not understand exactly what sex was and why we were having it and the consequences of it, or that we were having it at all. In fact, I'd be rather worried that anyone would think sex was a good idea in those circumstances at all -- what's the point of having sex with someone who is essentially incapable of participating in the act enthusiastically?
Notice the law doesn't say they can make this judgement based just on IQ, meaning that people who have mental limitations but do actually understand sex is happening, and that it can make babies and give people diseases, can still get married and have kids.
-----
" (5) "Mentally incapacitated" means that a person is temporarily incapable of appreciating or controlling the person's conduct as a result of the influence of a controlled or intoxicating substance:
(A) Administered to the person without the person's consent; or
(B) That renders the person unaware a sexual act is occurring."
------
If my husband drugs me unwillingly or thinks sex with an unconscious woman is sexy, I'd worry about myself AND them. Even my dad lost his boner when he and my mother were having sex on LSD and she said "You know, my grandmother was a beautiful woman." She probably did realize they were having sex, but was so totally not into it that HE wasn't into it.
------
" (7) "Physically helpless" means that a person is:
(A) Unconscious;
(B) Physically unable to communicate a lack of consent; or
(C) Rendered unaware a sexual act is occurring;"
------
Again, while some couples may be into sleep sex, that should be something discussed in advance. If it's not, I again would worry about my "loving" husband's proclivities and why he couldn't TELL me he had that fantasy and let me drug myself if I wanted to help him fulfill it. And if I'm ever rendered totally paralyzed, again, I'd be worried if he still wanted to get it on with me when I couldn't say yes or no.