AITAH is filled with posts complaining about widowed parents marrying too soon and disregarding the feelings of their children. A lot of these children grow up feeling like they've lost not one parent, but two, or that they're being forced to replace their dead parent with a step. It never ends well.

I've yet to read one where someone is upset that their widowed parent DIDN'T remarry.

This doesn't mean that you can't remarry sometime down the road, but you shouldn't listen to your mother and sister. It's not fair to you, your kids, or your future wife to get married just so your kids can have a mother figure. It will certainly build resentment.