Okay, this is going to be a bit harsh and I apologize ahead of time for it.
Suck it up and just do it. You already admitted to making the mistake of having sex with him, now you have to own your actions.
You are hurting him worse by ignoring him. Honesty is the way to go here charisma. The only way to go, and I think you know that.
I know you don't want to lose this friendship, but in your statement...