On more than one occasion she has said she can't show affection but wont discuss why in the house, only when the cameras aren't there,
It makes me feel maybe shes been abused in the past and that is why.
I have no evidence but just a gut feeling maybe that is why she is cold and aloof?

There's many reasons why she might not be able to show emotion. Sure, it might be past abuse, but that is taking a pretty big jump. It could also be something as simple as she's had her heart broken badly, or she just can't show emotion. Some people just can't.