In an ideal world, you've told your partner the truth about how many people you've slept with, you share the same bank account and - if Cate Blanchette is to be believed - you share the same email address.
In an interview with the Telegraph last week, the Oscar-nominated Australian actor said the key to her 16-year relationship with writer-director Andrew Upton and their "well-oiled" household was their joint email address.
"Opening up one's email account is the new going-to-the-loo-with-the-door-open relationship frontier," wrote Zoe Holman in response on the Guardian'sComment Is Free, expanding on the fact that merging your lives in the digital world is now the new thing for couples to do.
But let's stop for a minute, shall we?
New trend or not, do we need to examine what aspects of our lives we're comfortable merging, and which ones we aren't? And does it say something about our relationships if we aren't?
All of these things - full transparency, joint bank accounts - are touted as the 'secret' to a happy relationship. But surely this depends on your own boundaries as a person?
A friend of mine, who got married last year, announced - before his wedding - that he was going to have to get used to only having a joint bank account. Puzzled, I asked him why he was doing that.
"Because you have to, once you've gotten married, don't you?"
Clearly my friend was singing off my some invisible hymn sheet of what you have to do once you're settled down, and it left me wondering who set these rules in the first place.
I love my husband, but I couldn't think of anything worse than a joint email address. In the same way that I don't want to scrutinise when he buys (yet another) Ramones t-shirt, I don't want to have to justify buying (yet another) handbag.
I couldn't imagine of anything more irritating than having to sift through his subscriptions to Haaretz and The Onion, while I'm trying to find my HuffPost Lifestyle and Mind Body Green newsletters. Or wondering what he's thinking about my friends sending me videos such as Goats Shouting Like Humans.
Surely the 'secret' to a good relationship is being able to cut through to the stuff you really need to talk about, that really affects the bones of your partnership than white noise about who bought what?
Sharing: it's overrated. And I can't think of this being a more appropriate sentiment when it comes to the dreaded "how many people have you slept with" question.
This happened to a friend of mine who asked her new boyfriend how many people he had slept with. Apparently, she said, it's best to start with everything out in the open.
But have we come to confuse openness with communication? I believe so. Telling a new partner (or even an old one) all your secrets like word vomit, when often they have no context to understand your decisions or situation, does not necessarily strengthen your relationship.
Consistently being able to talk to your partner about your fears, your worries however - that's a lot harder, and more rewarding.
I'd be really interested in hearing what other people have to say about this.
I wouldn't go as far as to join the growing camp of (happily) married couples who are living apart a la Helena Bonham Carter because they want more autonomy. (Mainly because it would break my hubbie's heart).
But I don't believe that as a rational human who has lived alone for more years than as a couple, that my life automatically becomes subsumed by another person.
And if we have to draw a line, then joint email addresses definitely is it.