Strangely enough I turned down proposals on both my 50's. Quinn I was rather angry at still, and no, he never asked again, and the romance is not continuing (although I could tell him to father my children).
On my trooper, I gently turned down Aric saying that I wasn't the settling down sort. Lost affection, but he said he didn't want to push me into something I wasn't ready for. We still do have a romance because the next conversation asked about adopting children and he's been sending me love letters. There is no further proposal though.