I think it’s important to note as well that the necklace represents both good AND bad times for her (even though in her most recent history it’s been all the bad stuff) but as you say, she got that necklace in jail when she found out she was pregnant with Henry, and now with her memories of having kept him I think her pain on that score will be easier. Similarly in the Echo Cave she said it would be easier to move on from her pain if he was dead – so I think when he dies she will no longer associate the necklace with so much the pain but rather as a reminder of her good times with Neal and the child that came from them.