B - I know it is very difficult but there may not have been anything different you could have done. Maybe there were signs but maybe not. $hit happens all the time to good people you just have to pick yourself up, dust yourself off, and keep moving forward. Attractive people get D'd, celebrities get D'd, the word D does not discriminate. I have just accepted that it is very much an individual thing and if in my EW heart she did not want to make it work and try then there was nothing I could have done.
Truthfully I just think that some people are not satisfied with just living. Some people are always chasing, not ready to just live the life of being married and raising children. Sure you can have date nights, maybe take a couples trip once a year or whenever but if that is your norm and your with someone who is no longer satisfied by that then what is next? You get married, you buy your first home, you have kids, you make some home improvements, you take some trips, maybe you buy a second home, you get involved with your kids and their activities, maybe you take some more trips, you get some hobbies, you have kids practices and school activities, etc. etc. etc. That is life......I just think for some people that routine gets boring over time so they start looking at what is next in their life. They start to wonder if that is all there is in life? So you could have done things perfectly but if your spouse thinks there is something else out there that is better, different, that shakes up the norm, that maybe brings them that excitement again, it gives them the feeling that there is more to life than just living or the feeling that they are no longer bored or that they still have life left in them to live.
I could be wrong but I think some people are just not satisfied, might never be satisfied, and it is all relatively to their position in life. I think that is why IMO D does not discriminate...money, trips, etc. might make life easier or give the perception of more fulfillment but to those people that have it eventually that becomes the norm as well and it just gets taken for granted.
Which to me further drives home the point of finding happiness within and I think in most of our situations the spouse that is leaving does not have it or is trying to find it.