She very recently suffered a miscarriage after a brutal attack, so it’s no wonder she’s in a dark place.
Burgess and Roman didn’t break up because they didn’t love each other, but rather because Roman was injured and moved to San Diego after sustaining a career-ending injury while Burgess decided not to go with him.
That happened back at the end of Season 3, and Burgess has gone on the Ruzek relationship roller coaster since then.
Marina Squerciati’s comments to TV Insider indicate Roman is as well.