Something different

So let’s start this off I’m not bi or nothing I’m straight(nothing wrong with the lgbtq) but me and my boyfriend have been taking about a threesome (2F&1M) girls are beautiful and all but they don’t Attract me sexually but the idea of a threesome is kinda scary and hot at the same time I’m scared my boyfriend will think the other girl is better then me and like leave me I know that sounds weird but all of that is going threw my head but it also sounds hot I just don’t know what to do have any of y’all gone threw this I want to know I’m not alone