If you liked One Night at McCools then you might also...
...enjoy the lesser known Irish comedy ‚About Adam’ (2000). Essentially the same premise: A chameleon-like X becomes/appears to be what the current partner wants X to be. Just this time X is not a femme fatale (Liv Tyler) but a seemingly perfect guy (Stuart Townsend) seducing his fiancée's whole family –in other words: this is ‘About Adam’.
So while ‘McCool’s’ is told from the male perspective, ‘Adam’ basically takes on the female point of view. It’s not really a chick flick though. For us guys there is a 20-year old Kate Hudson (as easy on the eye as it gets) and a charming, scene stealing Frances O'Connor. Might be interesting to watch both movies in one evening.