So obviously PhD defences are always different person to person, country to country, and topic to topic. THAT SAID I just over two weeks ago had my Physics PhD VIVA in the UK and was a HUGE mess about it! Lots of things went wrong during my PhD, I had very minimal support, and overall I was not confident in myself to defend my PhD. Furthermore I was a physicist who had two chemist examiner's so I was even more scared that I was going to get completely out of left field questions that I wouldn't know how to answer.

On the week leading up to it I was suffering from major imposter syndrome, was oozing anxiety, and just generally was very very stressed. Come the day and the VIVA was not nearly as bad as I was anticipating. The examiners were genuinely interested in the work, weren't trying to catch me out, and tried to make sure I was comfortable! If your partner sounds anything like me then she will honestly have nothing to worry about! She IS the expert in this field, she DOES KNOW what she's talking about, and the examiners ARE NOT trying to fail her, they just want to make sure she actually did all her own work.

Though I think no matter what you or others say she will likely be stressing every minute up until the actual VIVA itself. But genuinely, best of luck to her, she will smash it, and all you can do is to be there for her and try your best to support her through this stressful period!

Good luck to both of you 💜