I think the concern here OP is your frequent use of 'we' not to mean all three of you but you and wife + him. This is noticeable in sentences such as:
His actions make us think he is dedicated to our relationship
This appears to myself (and perhaps Dagferi but I am sure she will correct me if I am waaay off base) that you are placing yourself and your wife as a unit with your wife's boyfriend as 'other' . Since you are so
emotionally involved and call it it can come across as couple privilege. This does have a tendency to ruin some otherwise happy relationships so it behoves you to pay attention to the terminology and make sure you do not fall into that trap.