Why Would Anyone Feign Handedness?

This may sound strange but here goes: I'm right-handed and everyone in my family is completely left-handed. However, due to a right-handed injury which I sustained years ago, it's more comfortable to eat with my left hand. In fact, it's difficult to eat with my right. Anyway, about a year ago I reunited with a former girlfriend who is totally right-handed, always was. I've noticed she's recently chosen to eat with her left, which is quite visibly awkward for her. My partner has a low self-esteem and goes overboard to fit in with everyone she comes in contact with. I'm wondering if she deliberately uses her left hand to eat just to "fit in" with myself and the rest of my family. I know this sounds petty but for some reason it's driving me nuts trying to figure out why she does this. Any thoughts why someone would do this?