You say that your DH found out "early on", about your EA. But then you say it continued for 5 years. So, presumably, after your DH found out, you carried on behind his back regardless?
For 5 years, you have been messaging another Man, but sharing a life and a bed with your DH. So you have lied (by omission), to the man you are meant to cherish and love.
Tbh, I don't think you love your DH.
How would you feel, if your DH was e-mailing another woman, for 5 years? FIVE YEARS
This is wrong, on so many levels.
I would split up with your DH, and let him find someone who really loves him. Someone who would cherish. Someone who would want to actually be with him, rather spending hours on end, composing e-mails to another Guy.
As for the OM's life being more interesting than yours, you do realise that everybodies lives on Facebook look about 1000% more interesting than they really are?
He still probably snores like a train and has skid marks in his boxers.