To try again with ex spouse or not?

Been divorced for a year and a half. Wife (ex) re entered the work force and an affair with a married dude. We divorced shortly after I found out. My ex wife has asked me if we could try to put it all back together again. I told her no. We were married for 15 years, two awesome kids. When I drop the kids off at the ex'es house, she kept the marital home, I should have a million great memories of that house. I carried both children across the threshold for the very first time. Both children took their first steps in that house. Both children said " daddy " for the first time ever in that house. Both children took their very first step in that house. Opened their very first Christmas present in that house. First birthday parties in that house.... You get the idea. When I am sitting there in the drive waiting for the kids, all I can think about is that D-bag in my house, WHILE I WAS MARRIED, not only in my house but most likely in my BED with my wife. A million good memories are trumped by a few bad thoughts. How is that even possible? The only reason that I would consider getting back with her is because I know I was not the greatest husband, I have never played the little victim here. I never abused, cheated or drank too much. Just got a little too comfortable and maybe took things for granted. But damn, if she was having issues, why couldn't she have came to me and we could have worked it out and avoided her having an affair. I think she is seeing that now and really regrets it, but it's too late, right? I mean getting back with an ex spouse never works out, right? It would never be the same. EVER.