Never ever apologize for being honest! It’s the one thing that everyone should always strive for.
You both still love each other, right? Maybe it’s good to talk to each other about why your relationship ended.
Can I ask why you haven’t left your current marriage if there’s no more love in it?
And can I ask why there is not more love in it? Maybe it’s time to be honest in that relationship first before you go seeking love somewhere else, you loved your current partner at some point, how did this fade, what can you and your partner do to make that spark heat up again?