My name is sabrina. I found your email on that dating site. > I also love sex on the side. I have a loving partner but he is working 16 > hours a day and we have sex only once a week
People, I'm totally sure that "uma posição sexual" is not what they talk about here. They talk about sex with someone else besides their regular partner. I don't know what that is in Pt-Br, but it's most probably not "de ladinho".
Lilian has asked me to give my opinion here, although I don't really see why it's necessary. "Sex on the side" means sex outside of marriage or outside of the person's main relationship.
P.S. I am a native speaker of English and an English expert on this site, but any speaker of English could tell you this.
BTW, I also think that "um parceiro amoroso" may be the wrong translation. It just means "I have a partner and we have a good relationship, but I sometimes like to have sex with other people".
Yep, jp, I thought the best was to remove them. The quarrel has been really hard here, having been out of translation matters and transformed into issuing subjective opinions and even personal attacks.