It was an example I used, mistakes can be made in any relationship, despite the strength of the relationship, and the SO will react in whatever way regardless of the strength of that relationship. Some people may be impulsive and wreckless and make a big mistake even if that relationship was extremely strong, the temptation or whatever else could be a factor of cheating even if they have everything they could have wished for at home.
But I do believe a single event could change a relationship yes, it could be the catalyst. She has told me that her feelings stared to fray since that happened, and she became more detached as time went on. So to me and all I have to go with is that of which she has told me. I knew someone who was with a partner who was completely against drugs, this couple from what I knew were in a healthy and seemingly strong relationship, the guy goes and does some cocaine, she finds out, and then that's it, end of relationship.
I'm not saying in an instant she lost the feelings all together, but it was that event that started the decline in her feelings towards me, is that really impossible?
I am grateful for your replies and I also appreciate your perspective, I am not entirely unwelcome to a harsher or tougher view on the situation, I have pondered before on the perspective you have put forward. I guess really, as is my nature I'm optimistic and am trying to hold onto some hope that there is a way of reconciliation, I'm not completely narrow minded as to deny your possibility, it's just when I ask many of times is it because you just fell out of love or believe we are not compatible, or that you don't find me attractive, or you want different things from life, or that I wasn't good enough as partner or a father etc etc.. it always comes back to her replying with no, I was very happy and everything was great before the miscarriage, I cannot fault you as a partner or father and I believe we'd still be happy if we'd not suffered the miscarriage, so with me asking her to lay it all on the table and be upfront, blunt and honest, and to get that same response over and over ... It's all I have to go with