It's a really difficult one (my Mum has suffered in the past with depressiona nd anxiety) and the two things are linked, as you have identified. The anxious feelings feed the depression, and then the two potentially spiral, often with bouts of obsessive behaviour. Today's extended talking about her issues with food is an example of this, and again by keeping it at the forefront of her mind, your wife is feeding the anxiety.

I know it must be terribly difficult to not talk about it, but try not to - is there anything else you can do to diffuse her focus and do something different?

Not being an expert, but knowing some of the tricks, it is important that your wife is kept occupied (it might be as simple as making sure there is a newspaper to read, watching the telly, even doing some cleaning - but don't add pressure, as that may exaccerbate the situation), and not just by baby, and she already has some structure around the clubs and classes.

How well do you know your wife's friends, etc - would you be able to arrange something with them, so that you could maybe all go out together, or even just make sure that they are popping in/calling to check on your other wife while you are at work? But without what they are doing being overly intrusive, or obvious.

The arrival of your baby is a huge change for both of you. So, also make sure that you have the support and help that you need too.

As for the breastfeeding - it is a really, really delicate situation, as your wife may feel that by not breastfeeding, she is not supporting the baby, but, it might be better for both of you if she were to stop. Not only would you be able to share the feeding duties, etc, (which would be a little less for her to do) but it might be beneficial for her to then be able to take medication.

Sorry if that is a load of waffle, rambling, but there is no one magic cure for situations like this.