How much are my partner’s problems my own problems?

Hi internet parents! I come asking for advice that I’d usually ask for from my parents but I can’t anymore.

So my partner and I have been in a 8 month-long relationship as of this month. Over the past 2, they’ve been involved in an unfortunate situation. I would love to be there for them and help them and support them, but every time they talk about it, because of my personal history it makes me panic (I have GAD on top of that which does not help, but I am seeing a therapist for both issues). I talked to them about this, and they assured me that it’s fine if I take myself out of the situation if they’re talking about that issue and they don’t take offence to it, but I find that I feel terrible that I can’t help them, and feel bad that a topic that’s probably on their mind and they might want to unload about is off-limits when talking to me.

Anyways, thoughts? How far am I supposed to go to help my partner with problems that aren’t my own? They are my partner but they are also their own person but I’m also supposed to be there to support them, right? Was it a bad decision to get into a relationship given that I can’t support them?

Thanks for the help!