Dee, Kate and Emma, thanks so much for your supportive suggestions of how to get around this problem. Your example is very interesting, Kate - and I'm so glad your schoolfriend recovered! And Emma, I agree completely about the tranquillity which comes once the events have been fully digested and accepted, and that it's usually necessary to reach that point before emotion can be effectively turned into poetry/fiction/art.
Dee, I have often wondered whether to write it from her husband's POV and I think that might have worked well, except that the other plotline has a husband as the vp character and his wife has post-natal depression, so I wanted this plotline to be very distinct from that. Writing it from the husband's POV might make it seem too similar.
I've been thinking about this hard all day, and I've come to the conclusion that I don't really want to change the overall plot, so I need to find a way to write this character. Instead of moving away from her, which seems a sensible way to gain perspective on her (but has the problem described above) I am going to bite the bullet and instead move
closer to her by trying to write her in first person. It may be a terrible idea, but it might just work, so it's worth a try. I have wondered before about trying it for this character.
This would mean I had two 3rd person viewpoint characters and one 1st person viewpoint character in the novel. I think (during a discussion here) we decided there was no problem with having some vp characters in 3rd and some in 1st.
Thank you all so much - everyone who commented - for discussing this with me. It has really helped me progress, and has also given me a nice warm feeling that there are people here who are so willing to give helpful advice!
Deb