Lila and the ending (spoilers)

I have seen how the ending has been discussed here, and I am surprised that many say it is ambivalent. To me the ending is quite clear, and I believe most have forgotten the third wheel in the menage-a-trois, Lila. So allow me to share my thoughts on her role and motivations.

Early in the film there is a scene where Lila accidentally confesses to her sister that she is in a desperate state because she realises that true passion is absent between her and Tom. Traditional screenwriting dictates that after that revelation, and regardless of what Lila maintains on the surface, she will not go through with the wedding, unless we see some spectacular fireworks ignite between her and Tom. Lila has done nothing to wrong Tom, and should not normally be “punished” by the script to enter a marriage without love. But no "romantics" take place between Lila and Tom in the course of the movie, so with that in mind I expected the wedding was doomed.

Lila is a controlling perfectionist, and love is her “greatest accomplishment”. With that in mind, the big fight between her and Laura becomes even more loaded, because her love is not perfect. Everything that Laura says is true, specifically that Lila (and people in general) deserve to live with someone who truly loves her. These knives that Laura throw cut into already open wounds (as we know from the scene with the sisters), and while on the surface Lila is unfased, this is only because she is furious at Laura and will not crumble in front of her.

Finally the wedding ceremony then. From the way both Tom and Lila act when they meet at the altar, I didn’t believe for a second they would finish the ceremony. Personally I believe it is obvious in the faces of the actors, and then Tom’s vows. As the user brizzosaurus said here on the board, Laura is Tom’s inspiration, his “words”, and now he has lost his words. This is what he literally says, as he struggles to say anything at all, “Without words I have nothing, I have nothing”.

What he is actually trying to say is “I don’t love you Lila” but as we know him, he can’t.

As his voice trails off, Lila then says [precise quote]: “Maybe I should say it for you”.
She does not say hey man, maybe I should finish your vows for you - which I think many mistakenly believe was the implication. But these things that Tom had said did not belong in any vows he had prepared, and certainly no vows that Lila had prepared and could finish for him.

No, what both of them were mounting up to say as the rain hit, was that it was over.