Some have suggested that if the Mother does die, Future Ted and Future Robin might be a couple again, and this whole story is a way of Ted convincing his children to embrace their new stepmother. That is also not an appealing option; it's simply a cop-out, and one that would be a lot more tolerable had the show not gone to great lengths to couple Robin with Barney — a pairing that seemed ludicrous in season one but has evolved into a long-standing, meaningful partnership. We've gone through every single bro-code violation and long, torturous explanations of the subsections of said code to get to a point where Ted can be okay (at least mostly) with Robin and Barney marrying. If that's all just a hiccup on the way to a Robin and Ted marriage, that's pretty awful.Sepinwall:
The show is about putting Ted on a journey where he is going to meet this woman who's going to make it all better, and instead, their time together looks like it'll only last slightly longer than the Mother's time with the boyfriend who died in the 200th episode. It's not technically a cheat on the series' title — the show's not called "How I Got To Spend Decade After Decade With Your Mother" — but it's a violation of the spirit of the law, if not the letter. It's a dark, misguided turn in a show not built for it.
You can point to the Mother's own backstory as a reminder that love isn't eternal, tragedy strikes, all this has happened before, and all of it will happen again, and time is a flat circle, and THEY REALLY THOUGHT THIS WAS A GOOD IDEA?