How Do You Feel About Threesomes

Soo me and my boyfriend been together for 2 years and I thought about having a threesome. I've talked to my sister's and close friends about it and heard some things that make me don't want to try it 😂😂 He could go fuck off with her while I'm not around, like her more, leave me with a broken heart and last but not least I HAVE TO WATCH A GIRL TAKE MY MAN PENIS not that she could do it better but the fact still remains Someone help. Like that's really the only thing watching them engage with each other i don't know if it's just me or what