Tricky. It might be that right now, you both behave in a way so that the other person would marry you if you insisted on it. But after getting married, you might both stop behaving that way and then things go downhill.
We are not acting in a 'sales mode' after 10+ years, we clicked early on and are ourselves: no lies, no masks, no illusions.
Reading TFA was interesting as, according to that data, we are perfectly set other than the marriage question. We're both atheist, so for the religious question it doesn't apply though I guess saying "The three of us regularly go to the museum, watch sciency shows, etc." would count as attending a church. ;)