The last couple of occasions I've seen my daughter, she's run around chanting "David's bottom, David's bottom" which is strange, considering I'm the only man whose bottom she's seen and my name's not David.
Curious, I asked her mother, my ex, about this and she revealed the hereto undisclosed information that "David" is the name of her new boyfriend.
"So why is our daughter talking about his bottom?" I asked, to which she replied that my two-year-old talks about her grandfather's bottom, nana's bottom, her playmates' bottoms - it's just something she joyfully intones now she's discovered we all have one.
On a recent visit to the art gallery, I showed my daughter a reproduction of Auguste Rodin's exquisite nude sculpture The Prodigal Son and all she could do was point at the appropriate anatomy and exclaim "BOT-TOM!" So she's got form in this area.
Still, I'd prefer not to hear about my ex's new boyfriend's bum while breakfasting with my daughter and no doubt she'll feel the same about my future girlfriend's derriere. So what to do?
Separation, when it involves a child, is never easy; in fact, it's been the most difficult thing I've ever had to cope with. However, my self-pity has been tempered by the experiences of friends who've gone down this road themselves.
"Wait until your ex hooks up with someone else," they counsel, "that's a whole new level of crap you have to deal with."
Eventually, they say, the happy new couple wants to go away up the coast for weekends (with your child) or, even better, move up the coast for good. Maybe the new guy insists on being called "daddy", or, best of all, your kid decides to impose the name themselves. Just friggin' kill me now.
A friend told me how he picked up his then four-year-old son from his ex-wife's house, where she was living with her new boyfriend, despite his hopes for a reconciliation.
"That's until my son started chanting in the back seat 'mummy, doesn't love you, mummy doesn't love you', as I sobbed in traffic like a crazy person," he said.
Another friend said her son (who now has a great relationship with his dad) bonded "frighteningly" quickly with her new boyfriend, Peter, even asking if good ole Pete could be his daddy instead.
Ain't that fun?
So, I reckon I don't have it too bad. It's just me and David's bum so far.
Of course, it's also not unheard of for a new partner to actually make things easier between a divorced or separated couple.
I know former husbands and wives who'll share a knowing look with the new partner when their ex has one of their turns - like they're a tour of duty in Vietnam: you have to have been there to truly understand.
In the end,though, what's most unedifying about being a non-custodial parent is the indisputable fact a stranger has more freedom of access to your child than you do.
The new partner can drop around whenever they want, lift your child into their arms to kiss them good night, while you're left to prowl the cage of your negotiated visiting times. I can honestly say it's a feeling I wouldn't wish upon Joseph Kony.
When it comes to grappling with emotions like this, my brains trust of friends is pretty much united in their advice that "it gets better" as the child gets older.
So, if you're a father or mother experiencing this "new level of crap" - stay with me on this - we'll supposedly laugh about it one day.
Maybe even with David.