assalm-walai-kum I wanted to ask you whether it's a sin to imagine having sexual intercourse or foreplay with someone. I really need my query to be answered.

Probably as most thing appear to be a sin..

It's fine as long as you are married.

Ramadan Mubarak!

God knows our hearts. All humans, men and women alike, have sexual thoughts. God knows this. He created us, and all the animals of the earth this way.

Unless the sexual thoughts and imaginings become all time consuming, and lead to things like porn, adultury, lust (which is entirely different from sexual imagination) and other such sins, (or having dreams or fantasies about haram activities) I have never heard that it is sin in Islam.