You have made it much harder to come back from this by not being truthful about the physical aspect. He should have heard that from you, not the OM. If I were him I'd be thinking you took the easy route by only admitting to what YOU were prepared to accept the consequences for at the time. You need to stop protecting yourself.
The thing about affairs is that they are temporary for the person committing them, but they break and burn an entire lifetime of trust and happiness for the person left on the other side. You may have to accept he will never look at you the same way again.
If you stand a chance at saving your marriage, you must never try to explain away what you did. You need to hold your hands up and be prepared to apologise again and again and again for breaking his trust. You will need to prepare for a future of having it thrown back in your face every time you argue, snide digs every time he feels resentful or insecure. You will need to willingly sacrifice your privacy (phone, texts, social media passwords etc), until he feels he can trust you again, if that day ever comes. You must be prepared to suggest couples counselling and be there, engaged and on time for every single appointment. And ask him what he needs, what it will take, and listen.
I have to say though, if it were my DH, I couldn't forgive it, as much as I might want to. It wouldn't stop me loving him and I think my heart would want to fight to make my marriage work again, but my head would tell me that a future spent second-guessing his fidelity is no way to live, and sadly I think that may be the truth for most people.