There seems to be something fishy between my boyfriend and my best friend. Should I expose him?

If it is not too much, don't ask! If there is nothing to do, something will happen when talking, but what should I do if I can properly isolate the distance between my good friend and my boyfriend? If you do things behind your back and your boyfriend doesn't tell you, there is a problem. In this era, girlfriends and boyfriends can't let them get too close, and girls are jealous.