It sure felt like a privilege to watch a film like that... Nothing like the average, fully predictable recipe-based product of the rather decaying modern American movie business. Unlike many recent films this one was actually based on real characters, let alone on real persons... I feel the objections expressed round here are exactly because of that: real people are not predictable, their "lines" are sometimes "blurring" the "clear" picture an average viewer -like myself- is used (or rather has been taught) to expect. Characters based on reality often make us feel a bit awkward form time to time. This, I think, is just because real persons are like that too...
I give credit to the director for choosing an eternal question as his theme, and to most of the actors for achieving to convince me, not just act very well. It somehow feels natural to watch the characters, some almost bizarre, just being themselves. The power of confession -through experience, sharing and expression- is, I think, what could turn a sinner (even a puritan) to a saint.
As for the desired equation (love=sex=eros?) it is not conclusively expressed, but then again, is there any human research that ever comes to a finite end?
In my opinion, the above qualities form something of a rarity, a sheer luxury, so seldom permitted by showbiz moneymaking machine nowadays.