The first year sucks because you are coming to terms with fall out and destruction of the affair. You are fighting fires.
And then the second year sucks because it is now part of your life. You realize it isn't going to go away in the ways that you hoped(I was going to love it all away). That R is a process and hard work.
One of my favorite posts I ever read on this site was a poster talking about how she got addicted to the apology letter. How she looked for them on special days, how she loved the emotional payoff from them. I do it no justice here. But that post made me realize for the first time that there were moments on this roller coaster that I relished as much as I hated others.
But the bottom line is that you move on, even when you are not ready to, you move on to the next stage.
The Heightened emotions and release of the early stages of R have plenty to offer in immediate payoff. Over time that erodes.
The second year is about adjustment, at least for me it was. this is going to be with you for awhile.
some people go through the "Plane of lethal flatness" where they go into protective mode and don't feel much of anything. I was too desperate for that.
But there are good things to look forward to. He pulled his head out of his butt the second year. We had our first real intimacy the second year. We made time for our marriage which we had not done for most of the previous decade. I started to get to know him again and vice versa. The sex got better for me because I wasn't trying to prove anything to him or myself anymore.