Mixed up ending limits film
The first two thirds of this film were quite good, and it played well as an off-kilter romantic comedy. Jessica Stein's character was well acted, and the pretense of two straight women approaching a lesbian relationship as some kind of alternative to the straight relationships they have had was also believable in a comic sort of way.
Unfortunately the last third of the film switched it to a more romantic drama from a comedy and the things that made it work were dropped, to be replaced by the more "serious" aspects of the relationship that weren't addressed well or even explained well.
I thought the issue of "coming out" as a lesbian couple (at the wedding) was handled too abruptly; even for Helen, the notion of suddenly being "out" as a lesbian in a relationship would have had more gravitas than it did, and for an essentially middle-class suburban Jew like Stein would have been almost unthinkable. To start and essentially finish it with a sudden confrontation at the dress shop didn't do the subject justice.
The issue of sexuality in their relationship was handled far too obliquely, for, as Helen explains as she's walking out, what they had was a friendship, not a relationship -- the sexuality makes the difference in whether its a friendship that's gotten ocassionally intimate, or a real relationship.
Did Jessica's sexuality issues extend to men? Was it just the fact it was lesbian sex that was a barrier? Is there something ultimately unfulfilling about lesbian sex for an essentially heterosexual woman? These are deep issues that an entire movie could be based around, but Jessica is just played as not wanting sex with Helen and we're not given much motivation to ponder.
It would have played and developed better as a comedy if they had focused more on the comedic aspects of their relationship; "coming out" has a ton of potential for comedy of errors. Jessica and Helen's sexuality could have been turned on its head to great irony and comedy if the bookish and conservative Jessica had instead been turned into the man-for-every-need Helen, and if Helen had instead become more conservative. It would have played nicely into figuring out what each character "really needed" -- Jessica more release, and Helen more depth.