How not to be insecure?

How do you trust your significant other not to do the shit you think they may be doing? Like for example, she goes to sleep at a friend's house. How are you not trusting her friend didn't bring 1 hot guy and is having a 2some? Or 2 hot guys and having an orgy? My mind tells me everytime she takes a min to answer "SHE'S GETTING FUCKED!"

Insecurity is a nasty nasty feeling. Tbh I don't trust anyone. Not even people in my family but this Insecurity kills love which is cool