Board Thread:General Discussion/@comment-25926288-20151026005934/@comment-1894786-20151102000911

Canonically, Robin and Regina knew each other for a year, fell in love during that year, got their memories erased, met again, fell in love (again!) over the course of a week or two, spent two more weeks having an illicit affair after Marilena showed up, spent 6 more weeks apart, then were reunited for another six weeks and now we're at the present day.

So by the time Regina shed that tear, she was probably with Robin longer than she'd ever been with Daniel.