I don't totally agree with this, but I will say I actually loved Remus/Tonks until the last book. I was an R/T shipper right after OoTP. I don't think JKR forced their marriage to make the death more tragic; I think she just forced the characters in, full stop. It felt like she wanted them in the story so made room for them (where it didn't make sense) rather than letting it come naturally. I wish she'd written them more like Bill and Fleur, who had a wonderful love story - which worked because it wasn't forced at all.