Just focus on your son, he's the only important thing to come out of the relationship. She sounds like more trouble than she's worth as a friend or girlfriend so the most important thing you can do is suck it up and be civil. She just wants drama. Don't give it to her. Kill her with kindness.
So, so you think you can tell Heaven from Hell,
blue skies from pain.
Can you tell a green field from a cold steel rail?
A smile from a veil?
Do you think you can tell?
And did they get you to trade your heroes for ghosts?
Hot ashes for trees?
Hot air for a cool breeze?
Cold comfort for change?
And did you exchange a walk on part in the war for a lead role in a cage?