Critical:Help! I’ve Slept With My Best Friend’s Fiance, Should I tell Her??

Omo i no go lie  but this wednesday question abi na dialogue o critical. Please everyone lets be of help to everyone we meet in our way and daily is the word i would love to use.
Here is what a lady sent to me via mail and she needs your audience and opinion on this.

I’m a 24years old lady who manages a restaurant at Opebi. However I am in a fix and I need the
advice of your readers on this one.
l have been friends with this lady (I will call her Bola for privacy reasons ) from my teenage years, sharing many fun moments together. Bola wants to get married now, however the problem is that the guy she wants to marry is a chronic womaniser.

While Bola and this guy were courting, he made passes at me (and I am ashamed to say this, we actually slept together) and a couple of other girls I know.

I have tried hinting Bola about this but she seems not to be receptive about it
(you know what they say about love been blind).

I don’t want to lose my friend and I also don’t want her to marry this guy not for selfish reasons though but for the reality of things. How should I go about this?.

Please comments would be appreciated