Looking for something similar to this for my main sim to wear, preferably as lingerie.

This is the closest I have come to finding what you are looking for. I downloaded this with the same intention as you... only this is not available in pajamas. Which really made me angry. If you know to reassign the outfits, this might work? http://customcontentcaboodle.com/tag/lady-gaga/page/30/

Looking at this some more, it reminds me a lot of the robe that Britney Spears wore in her "Lucky" video. I went on a Google search, didn't really find anything... I know this is what I use for my rich Sims though when they want to lounge around the house! Good luck! LINK >http://www.all-about-style.com/Sims3hist_female.html

This one maybe. http://santosfashionsims.tumblr.com...own-recolorable

I found these:

(NSFW) http://hello-domo-bear.tumblr.com/p...-for-adult-both
http://meronin-sims.blogspot.com.br...2013-dress.html

I already have everything from AllAboutStyle and that Gothy looking Alexander McQueen version, so I got the Rihanna and Lady Gaga ones (I can convert the Lady Gaga one to sleepwear) and the transparent one enabled for maternity and males since I could always use more maternity constantly playing pregnant sims along with male maternity since I play pregnant male sims and to give my male sims a chance to feel fabulous... thanks everyone!