Advice

I have seen this guy for like four weeks and last night be are hanging out in my room and we start getting turn on all of the suddenly we doing some sexual stuff.we are not in a relationship we are just friends.because I'm not sure if he was telling the truth that he is single or not.i email this girl that I saw that she have a relationship with him and ask her if they are together but she didn't reply me back so I'm assuming they are not together because she didn't respond me back.otherwise it will be something worst that she will cussed me out.it makes me feel good that I did but I'm just want to knw what you all thinking of that ?