How contagious is moldy bread AND how to handle this roommate situation?

1. The top slice of a loaf of bread had a dot of mold in it. This suggests to me that smaller, not-yet-visible mold bits have permeated the rest of the bread. Can I eat it anyway?

2. My roommate went on one date with a friend of mine who never called her again. Obviously this friend was a total dick and I have verbally eviscerated him for it. Naturally, she hates running into him. Am I obligated to never invite him over, or even to meet me at our house? I went for a run with said friend last night and when I told roommate who was knocking she shut herself in her room for the rest of the night and didn’t come out. (I like my roommate and do not want to alienate her.)