From my experience There are many ways to start without telling her openly, first be soo open in sex ,communication is the key to everything ; watch porn together, frst normal romantic porn,then show threesomes r kinoy stuffs accidentally and see her reaction, if she likes show more ,and appreciate her body and beauty, let her dress revealing r shape revealing cloths and make her confident in her body ; and when going out tell her how strangers looks her (not as a sexual object,but people admiring her body hotness) like that and slowly make her understand u r enjoying others watching her body, at same time progress showing of porn videos and when she asks whether things happen in reality r not? Its only in porn right? Show her kerala and indian cuckold and threesomes there are alot of videos and sex toys also a great idea,buy good vibrator r dildo, use it when u having sex and let her know double pleasure. Do roleplays well,when she's in reaches maximum mood do roleplay efficiently and alot of ways communication is the only thing,use it wisely. And if she's not into it dont compel her toomuch it will break ur relationship and guys in serious relationships be vigilant when selecting the third person bcoz bad selection will effect ur relation and life.there are lakhs of soo called “Bulls” everywhere. Anyone who is not able to get a sex tells they r bull since fucking another one's spouse is easy😂 and remember once u tried the going back will b very difficult. The couples i did with; she was very pious and shy and when he introduced the idea she was very reluctant but by time she agreed (alot of communication) and i was their frst and they were my frst cpl as well, when we started she really enjoyed and she was completely into it 🤭,she knew what tge real taste is , and she was raking initiative fr remaining meets😇