"he tried to tell me it was an xmas gift for one of our kids"
There you go. That's how far and willing he is to save himself in this thing, should you be wondering.
You have every right to know everything and no less than that. He opened Pandora's box, and now that you have access, I really don't see how he can even pretend to claim any kind of moral highground.
Yes, he may feel regret, remorse, or neither. It's all irrelevant now really. I know it doesn't feel that way, and you don't want to feel this way, but prepare yourself to protect yourself.
When I found out I made a calendar of their meetings and conversations spanning months. He hardly willingly revealed anything, I pieced "it" together based on email correspondence I found. Believe me, I didn't want to be doing any of this, but he was being so vague and I had no choice for my own sanity. And I was trying to figure out my future, so I had to know how deep his deceit went.
So I completely understand, details are really important in revealing intent and belief.
Be forewarned, knowing the details never answered the "why did you do this when we were so happy" question. What answer can a cheating spouse come up with to really fix that damage? But demanding and expecting specifics and answers put me back into the equation of my own life. It was time to re-evaluate things.
Isn't it the least our "wayward" spouses owe us? To answer why? At least those of us who chose to stick around and give them the time for an honest answer and perhaps a second chance.
I suppose my advice to you is to trust your gut, follow through on finding out the "details" and specifics of your situation as you need to, and decide nothing, promise nothing, until you have the facts and know what you need to know to make a decision on whether the person you trusted and loved until now is still worthy of your love and devotion. Suspend your judgement for the time being.
Try to step back, protect yourself emotionally and your children (if you have little people to protect). I know that may seem impossible after what happened to you, but it's really important you try to be objective right now.
My WS went into deep therapy after his big F Up. I would have never predicted it because I was out the door already, but it turned out to make a difference in my decision to stay with him and try to retrieve the "good life" we had before, even as I questioned if any of it was possible or was even true.
I wanted nothing to do with him after his "dalliance". He wounded me so deeply it took years to recover. And recovery wasn't my first intent. I wanted truth and answers and out. I wanted meaning in my life again. I wanted an explanation to why he sold us so cheaply.
I'll never trust him like I did before. He has left me with the gift of vigilance, ie trust nothing or no one. Actually, neither he nor I will ever again live in the security we had before. With each other or in the world. Just that alone really pisses me off. What am I supposed to do with that? Or that HE was the one to gifted it? He really F Up our plans and lives.
It's been five years. Yes it took me that long to want him back. I stuck through it mostly because he fought so hard to keep me from leaving. I'm finally seeing him again as I did before he F Up. And I loved that person so so much, I'm so glad to be able to see him again, to see us again.
Still, as glad I am, a part of me has disappeared. I told him so. "She" is gone to you. Nothing can change this. But she's not gone to me. I don't know if I can convey what I mean exactly. The best most trusting part of me is now reserved and private and safe.
I realize I've gone on and maybe off topic. But this has been my experience and I have no regrets about my questions or expectations after discovering the affair. I didn't think we could ever recover, and I didn't necessarily want it, but I had to know what went on behind my back to have peace.