It won't be awkward and strange all the time

The throuple dating can be awkward and strange at first, but it can be awkward and strange when you first meet someone you've had sex with. A lot of it is social programming, but I think it's also human behavior. Although sexually active people like to say it's "just a physical activity" and you can exclude all emotions, there needs to be some kind of interaction at the end of the day and chemical reactions can be found before sex. Even if the threesome partner comes to your bed, take the time to get to know each other and build up some sexual chemistry.