Why jump to 'sex addiction' ?
Thats a reach.
Or is he talking that guff as an excuse?
Because I'm sorry op but it's much more likely he just doesn't give a shit about you. He's only sorry he's been caught. Because now he might lose his kushy life.
No therapist can therapist empathy into a person. Or, respect or love or general basic human decency.
He doesn't have these things. If it was a sex addiction and he did, he could have told you. He didn't. If he cheated once he could have told you then and asked if therapy was possible. But he didn't.
He doesn't want to change. He just wants to con you back into ignorance.
He doesn't care a jot about you. Infact, he's been laughing at you for years. Sorry hon. But you deserve better. Don't flog the dead horse. Choose yourself and get free of the vile letch.
He's not a sex addict. He just doesn't like you. And even if he were a sex addict, that's not the issue...the issue is...Well again, that he just doesn't like you.