Actually I have done it a couple of times. Well, one of them was more like six months than a year. We had dated for a short time around five years earlier.
The main one is someone I have gotten back together with, more times than I care to count. I think I'm actually over my obsession with this person, finally after 25 f**cking years. But yeah we had a couple on-and-offs in the late 80s/early 90s (he was basically the town hottie back then, and had a lot of women interested in him; sometimes he'd be interested in them too). We got back together in 2007 and stayed together for a little over a year, probably spending on average 5 nights a week together; then split up for several months, then we got back together again and were on-and-off for a while until my feelings for him changed abruptly. I don't even bother breaking up anymore however, it's just ridiculous after getting back together so many times.
But although we haven't officially broken up, for the past year or so we rarely see each other, and we aren't physically intimate anymore (although he may not realize that last time was the last time; I haven't actually told him). Right before that, we actually lived together for maybe six months. He came & stayed at my house; thankfully, for some reason I was finally able to see the truth of the relationship during that time. I finally realized he doesn't love me, and it's like a curtain came down. Which is a blessing, because he's very high-maintenance to be in a relationship with as well as it being an emotional rollercoaster.
So I asked him to leave and he went and moved in with one of his guy friends who lives about 20-30 miles from here.
That's how things stand now, but when we first got back together in 2007 after 15 years apart, it was quite wonderful for a while. I was so into it that it rarely occurred to me that he was really using me a lot and giving very little of himself ~ and all quite blatantly too, in hindsight. (This has been a pattern in my other relationships as well.) He'd probably still say he loves me even now, but then disproves it through his actions if I let him get too close.
So getting back together had its moments of goodness, although it turned out not to be permanent. It was enlightening and helped me get some "closure" ~ and lots of it, lol.