I don't think of myself as a bad person, yes i have done this horrible unspeakable thing, but i don't think of myself as bad. Maybe i should.
I have a few thoughts about this. I am not saying this to shame you, because I do feel like shame, low self worth, etc, all lead to why we look to be validated by others. And, the more shame and the lower the self worth the more we need of that and the bigger the hole we find ourselves trying to dig out of. I am pretty sure the largest majority of affairs outside of maybe personality disorders or other mental illness have a root cause of self worth and shame issues.
So, it's interesting that you don't see yourself as a bad person. I think that perhaps you have to look at your morals and integrity. I had to do this as well, so this is not a slam. A poster once suggested to me that I had an affair because it was not against my morals to do so. It's an interesting thought, and when I weighed that, I don't think that's really true. I think it was against my morals and beliefs. So, that brought me to the thinking of why did I lower them? I had been an exemplary wife for decades. I had been a doting mother. I had always achieved a lot at work. Thinking of this bad person thing, well that just wasn't possible to me.
And at the end of the day, none of us is all bad or all good. But, at the time we are needlessly hurting and lying to others - if this was someone doing that to your sister or mother, would you not color them differently? How about your daughter? So, I will not insist you to think of yourself as a bad person, but you have to think about what your own integrity means to you, what your moral compass says about it. And, why were you willing to do it?
And, why can't you see that someone willing to do it with you did not have your best interests at heart. She was there for you to give her that same validation that you are seeking. She used you for that and left. She helped you hurt your wife and the mother of your children. Putting your children's security and happiness and chance at a whole home at risk.
I think it's important for you to look at the stories you are still telling yourself to feel better about your actions. You are still excusing yourself because what you want and how you feel is more important than upholding that integrity and moral code. By ruminating on the things that are true about the affair rather than just craving the high feelings that it gives you, this is your way back.
I think the prospect of building a new home together could be a very lovely and symbolic thing. But, don't start this process now. Instead, rebuild yourself, and if you are still given the chance then rebuild your marriage, and when that is done then maybe consider building a new home and a new dream together. But, right now your situation is not stable, and you are still looking for band aids.
There is no band aid. You talk about looking towards the next best thing to happen....Well I can tell you as a middle aged person who suffered from some of those thoughts myself...happiness doesn't just happen when you do x, y, z. Joy is something you have in your heart regardless of your circumstances. Pema Chadron has some wonderful thoughts that might help you connect with the truths about joy. Happiness is not in the future or in the past, it's today. Today is all we have. Part of your problem is living in either the past or future. Your life is right in front of you. Be mindful of it.
One thing that helped bring me joy (other than running, I get a lot of mental stability from that and I believe it cures cycles of depression that I used to find myself in) is to have a gratitude practice. Every morning I wrote down and really reflected on 3 things I was genuinely grateful for. I would really connect with the happiness, simplicity of that. What I found was after about a month of this, I had actually started to notice all those things a lot more. They began to give me these little sparks of joy throughout the day. And some of the things I appreciated were about my husband and family. It reminded me how much I wanted to give back to him.
And, at the end of all that, what I learned is the greatest way to experience love is to give it. Concentrate on your actions and the genuine giving in your heart that you want to give to your wife. You don't really experience love by being loved. You experience it in giving it. That's also where a big well of joy can be found.