My boyfriend wants an open relationship and I'm not too keen on the idea
Open relationship?  Why did he say so? 
He just said he likes the idea of polyamory.
Wow,  so,  are you going to allow that?  Can you share your man?
Infidelity
Infidelity (synonyms include: cheating, straying, adultery (when married), being unfaithful, or having an affair) is a violation of a couple's assumed or stated contract regarding emotional and/or sexual exclusivity. Other scholars define infidelity as a violation according to the subjective feeling that one's partner has violated a set of rules or relationship norms; this violation results in feelings of jealousy, sexual jealousy, and rivalry.
What constitutes an act of infidelity depends upon the exclusivity expectations within the relationship. In marital
had no idea, they had no idea. So I said, 'What are you doing here?' She looked at me and said, 'What are you doing here?' And I said, 'Well, I'm reading for the lead guy.' I said, 'What are you doing here?' She said, 'I'm the mother!'" Cassidy discussed his relationship with his stepmother on the show: "She wasn't my mother, and I can be very open, and