We're doing this now 
DD is 6.5mo. I went back to work at the start of December. DH had been off a week, so we had a week off together. Because of annual leave I've accrued I'm working two or three days a week until the end of the year, easing myself back into it!
And in all honesty, it hasn't been as bad as I expected so far. I'd already built up a freezer stash of milk but we've found DD doesn't drink that much while I'm at work. I express twice a day at work (once on my lunch break, then once later on in the day) and I seem to bring home more than she drinks!
I don't start work til 10 so that helps in keeping our mornings quite low-key. But so far it tends to be:
I wake up, breastfeed DD, leave her in bed with DH while I get showered and dressed, he changes her nappy etc
Take DD downstairs while DH showers
DD and I have breakfast - usually we share toast and a banana (though she doesn't actually "eat" much, has a good suck though!)
Then DH will come down, between us we get DD dressed and bag ready etc, drink coffee, he then gives me a lift to work
I don't finish til 6, so it does mean that DD's bedtime has been pushed back a bit what with her wanting a feed when I get in etc.
The thing I've found toughest is being tired at work if we've had a bad night's sleep. But I honestly find being at work less tiring than being at home all day (which I think DH is realising too!).
Sorry, that was long. But really I'm glad we're doing it; it's good for me to have a bit of adult conversation and time to myself, and it's definitely good for DH to appreciate what a full day of childcare involves, and for his bond with DD.