How can I best help my wife breastfeed? She has some problems with one breast and loses confidence when she tries to feed with that breast. However I know it's important she uses both breasts to prevent swelling or mastitis.

In fact, one very good way is to massage her breast so that it stimulate milk production. With having more milk, it may help her to feed/latch more confidently and giving her the idea that "Yes, I can do it. Baby is drinking and emptying my breast." Give her assurance that she is doing a good job. Tell her things like baby is still learning and it takes time. Meanwhile, you can either hand express or by using a breast pump to assist you so as not to engorge the breast that is not latched on.