Some ancient culture, consider widow and widowers to still be married, so can't remarry, thought?
For example, in ancient China, even after ur spouse passed away, u are still legally still married to him/her, if u want to be remarried, u need to get divorce from ur dead spouse. Ur spouse's parents, act on ur dead spouse's behalf, in divorce, if ur dead spouse's parents are also dead, then the dead spouse's children act on his/her behalf, if he/she got no kids, u need to find a medium to communicate with the spirit of ur dead spouse. So, it is not exactly, dead till u part, it is more like, divorce till u part.
Life is for the living! Each of us runs our own race. It's hard to imagine someone who truly loved you to not want you to go on living a (happy fulfilled life) after they are gone. Nevertheless people are free to choose their own beliefs.
[ you would be prettier if they broke your feet from childhood so you could barely walk.] That is true, I don't know why some people from that era think that way, they passed a law to outlaw it earlier, but couldn't fully enforce it by 20th century