I believe that intentional exposure to diseases needs the consent of the person exposed. Our son has had three opportunities for chicken pox exposure, he has declined each time, at age 3.5, 5ish, and recently at age 7. I believe there will be plenty of opportunities for him to acquire them naturally, or agree to exposure as an older child.
We discussed this with him when opportunities arose to acquire wild chicken pox. And he declined intentional exposure to the chicken pox at that time. There are risks to vaccinating (we are completely non-vaccinating) and there are risks to the diseases. To intentionally expose anyone (child or adult) to diseases (through vaccines or organically) against their will, or without their informed consent, is very uncomfortable to me.
I would also assess your husband's chicken pox history, before actively choosing to expose any children. If he has not had the pox, he might consider vaccination, relocation for the duration of the outbreak (2 weeks+), or intentional exposure at the *same* time as the children, in order not to be a full secondary household exposure. We had chicken pox titers drawn on my husband to ascertain his immunity status, as he only recalled "maybe one or two pox". For any adult to acquire secondary exposure could be highly serious.
Also, consider the potential for exposure to other members of your family (especially at holiday time), or others in your playgroups who are pregnant (especially first trimester, without prior cp) over the 2nd-4th weeks post exposure. And avoid airplane recycled air during the 2nd and 3rd week post exposure. Airplanes could disseminate chicken pox in a lethal manner to those who are immunocompromised.
I also think her chance of acquiring chicken pox is unlikely due to the extent of nursing still (assuming you have had chicken pox). However, you'd need to take all precautions to protect others from exposure, during any potential duration of contagion.