What to think about my boyfriend and bestfriend confiding in each other?

any thoughts on this would be appriciated, my boyfriend and i had a few problems at xmas time, instead of talking to me he confided in my bestfriend who then went onto tell me what had been spoken about between them, thankfully boyfriend and i sorted things out thanks to the chat he had with my friend, but today i came home from work and found my bestfriend in my house with my boyfriend , she claims she forgot i would be out, it seems as though she came over to have a cry and moan about her own relationship probs to me but ended up crying on my boyfriends shoulder, am feeling a bit cheesed off she was here for so long talking to my boyfriend without me here, so now they both have confided in each other about problems and my mind is thinking alsorts, do i just brush this under the carpet and be glad my boyfriend and bestfriend get along or should i be wary and keep an eye on them.