I think this is a good example of how lying can affect one's autonomy (though I don't remotely hold that as an absolute principle). In the ideal exercise of love, I agree with your claim. I don't think it's dismantled in practice, but I think it is weaker. The spouse fell in love with "someone", but it turns out it's just a dummy of the other spouse. To some extent, probably everyone only loves or even perceives imperfect images of others, but this takes it a step further. I think this is somewhat different from supporting a disabled/ill spouse, because that condition arose through no fault of anyone (presumably). I think this is also different from a spouse, sometime into the marriage, realizing a different romantic/sexual orientation, because no one could've known at the time of marriage (presumably).