I always thought this was true since I saw the movie and was recently made aware this isn't what most people think.

https://imgur.com/a/vxZPoEi

She uses Forrest when it is advantageous for her but will dip out regularly when he needs her. Forrest tries to do good his whole life but constantly has Jenny show up randomly to rock the boat.

Then at the end of the movie she leaves a kid with him that clearly isn't his, and if it is his how awful is it to hide a kid from his father for that long. He probably would have taken in the child out of his love for Jenny if she would have just told him the truth too.

Edit:wow people didn't like this one.

I don't hate Jenny, I think she is a well done character. I was just think think she is the villain of the movie, which isn't a bad thing. I definitely don't care if she is a girl, that was not the point of the post.

I did say worst to stir the pot a bit. There are clearly much more evil villains, obviously..