Ultimatums, don't usually work. Ending things, over this, meh, that could be seen as overreacting.
However, your feelings, aren't an overreaction.
I'd be very hurt, and confused over the parents remarks.
I get, the hurt, over lack of being introduced, to his toddler, especially after moving him into your life, and your children have bonded to him.
Your kids ARE asking questions. That's, the 'tug', imo.
You don't seem, to sound satisfied, with the excuses made. Plus, the parents comments added, to the mix.
Are you having second thoughts, with him, in your life? Anything else, adding to the mix, of wanting to end things?
Sent from my LG-MS910 using Tapatalk 2