I read an interview with the creator and a couple of the writers a few months ago, they said that they hadn't made any plans about the mother, who she will be or anything about her and ted, other than the two kids he is telling the story to. The show is basically the a twist on an persons journey to find 'the one' With the twist being that is had supposedly all already happened and is being told as a story to the teenage children of the main character.
Well - I thought of two possible explanations for that theory; one slightly more morbid than the other.
1) Teds wife had been dead a while when he is telling the story. He spends a lot of time rambling especially about how good he and Robyn were together. Maybe this is his way of trying to tell them that he and Robyn are getting back together. (Barney is dead/divorced in this scenario). This would SUCK as I hate Robyn (and love Barney) but would explain why he goes on about Robyn so much to his children.
2) Teds wife has just died - and he's trying to tell them but is rambling because he can't face it himself.
A few things indicate the mother is dead - the whole wanted to spend that extra 45 days/seconds with her for example. Plus in one episode Lily, Ted and Marshall go to a high school reunion and get high. In that scene Ted says "where's my wife?" and then descends into what could be either laughing or sobbing.
I thought of that, but don't the kids look reasonably cheerful when we occasionally see them on screen? But that doesn't rule it out of course. Also, though, wouldn't it make for a really depressing end to the whole thing? We find out who she is, they get married and live happily ever after...but then she dies and Ted spends all his time reminiscing about his friends rather than her?!?
Yikes, never thought of it that way, I've only been watching it for a while, I think I need a boxset to start at the beginning. I watch on E4 and it's either repeats or one episode doesn't follow the previous one, I get confused
But I do love it, think it's very funny, will organise boxset asap