ok, i will throw in my 2 cents worth.

having had 4 children i wil tell my side of the story.
while preggy my husband- who is very nilla!- just wanted sex, i dont think he actually really cared one way or the other about what i looked like, as long as he could get layed!
he used to say to me " what about all these women who get super horny while they are pregnant? how come you arent like that?"

for my part? sex while pregnant was just yuk. i had morning sickness all day for months, i felt tired, sex? NO
i read somewhere that some european country, i think maybe Italy, had a tradition of once the wife was pregnant, he went out and found a mistress for the next 18 months/2 years. which sounds like an excellent idea to me!