The old bachelor saying is that "friends" are just girls you haven't slept with yet. For as long as you've let this go on, I'd bet they slept together.
"Friends" of the opposite sex are by and large inappropriate for married people and lead to human stupidity.
H 34 W 29 BD 3/12/18 Divorce Busted Spring 19
It is not things that bother us, but the stories we tell ourselves about things.