All you can do is keep apologizing and acknowledge her pain. If she doesn't want to talk about it, that's her wanting space and you should give it to her.
Romantic or marital betrayal is a hell of a thing. I've seen it said many times that it hurts more and cuts deeper than the death of a loved one, and I can say that's been my experience as well. The average time frame for recovery is 2 to 5 years. Yes, years. And true reconciliation can be a lifetime work in progress.
It sounds like you're doing a lot of the right things. A few small tips tho - don't minimize (ie: "it was only") don't rugsweep, and don't say things like "it was x amount of time ago," or "we need to move past/get over this." Do not shift any blame to her, the marriage, or some external source. This looks like "we grew apart" or "I felt alone" or "I wasn't getting what I needed from you" or "I was hurt and in a bad place" or "my mother had just passed" or whatever. None of those are legitimate reasons to have an affair. Nothing really is, period. This is something in you that allowed your boundaries to dissolve and turn to someone else instead of your wife. She may not be responding yet, and she may never, but not enough time has passed for her to remotely be getting over it.
It's different for everyone. Some people can learn to live with it, some just can't, and that's just the way it is. Note that I used the phrase "learn to live with it." I say that because I'm not so sure anyone ever truly "gets over it." It's something that's now a part of your story and it can't be taken back. Maybe some do truly get over it, but I have my doubts. Some can learn to live with it, tho, and some can come out the other side even stronger than before, but I think that's pretty rare. It is doable tho, with the right people.
Be there for her when she wants, give her space when she needs it. And buckle up, because she's going to be on an emotional roller coaster for quite a while. Reconciliation isn't for the feint of heart. It's a long, painful process, and there aren't any shortcuts.