This makes sense now. Admittedly, I had my suspicions about the partner because I thought that his demeanor was shifty and he was hiding something, but now that these facts have come to light, I understand why he was uncomfortable in front of the camera.
When asked about Nicola as a person he went on about how she lit up everyone's lives etc, which I don't dispute, but the fact was that she was battling with addiction, was depressed and vulnerable. It must have been hard for him to put a positive spin on someone who was apparently suicidal.
I think that, with hindsight, the police should have been more forthright with the family and set expectations that, much as they don't want to sully Nicola's reputation, they need to make the media circus aware that Nicola did have mental health issues.