Do you think that Charlotte...
wanted to kill the old man by giving him a heart attack with her sexual behaviour so that she could marry Lionel?
(who is possibly gay)
Or am I overdramatizing?
Charlotte was a very complex character. I'm still unsure of her entirely though you can guarantee sleeping with Lionel's Dad was to enact revenge.
"I'd rather be hated for who I am, than loved for who I am not".