In your Synastry chart you've got her saturn triggering your NN, and also her chiron conjuncting your SN, whilst also in sextile with your own chiron.
This to me is very interesting, as i know a little of your situation with her.
The SN points to past life links, so you and her were probably together or had something going on in a past life. Its the south node person who owes the planet person for hurting them in a past life, the south node owes the karmic debt.
Did she seem familiar when you first met her ? Was there things about her you just clicked with instantly ?
Maybe in your past life together, you was the one who left her for someone else and left her heartbroken, and this time around you need to be the one getting left and hurt by her to balance your Karma scales out.
Your the nodal point, so your the one feeling this most intensely...hence why you feel like you do.
Onto chiron....Chiron is, as we know, the wounded healer, somebody gets hurt and somebody gets healed (as its on your SN), you've hurt her in the past, you could have abandoned her, rejected her just like chiron was as a baby, she never healed from this in your previous life.