My bad! I had to go back and re-read what your xbf stated and at first, I thought he was referencing your being an only child, but when I looked at it again, if I'm not mistaken, he's talking about himself. Am I correct in my second "assumption"? If I'm correct, he at least is admitting his faults of being an only child and yes, even being selfish and the light bulb moment...not wanting to share. The not wanting to share is one that you can now understand better because of the way he's been w/the business and dragging his feet about putting your name on the documents to make everything legal.
Are you okay w/what he wants to do w/company money, i.e., lending it to her? Is he going to draw up paperwork and include finance charges for the amount that is being loaned to her?
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
