Protecting your best friend is part of your job as a friend.
Although it isn’t your place to interfere in the intricacies of a person’s relationship as far as what rules they have set for each other as two adults, it doesn’t mean you should apply this courtesy in every aspect.
Seeing your best friend’s partner with an active account on a dating site is one of those exceptions.
There is a reason why your instincts are on red alert.
A feeling within you persists, compelling you to believe that you are a side piece.
He declared you his girlfriend a while ago, and you believed him.
After all, he courted you properly, as he paid for dates and ensured you always got home safe by either texting and asking whether you got home okay or driving you back home himself.