No, you won't lose your voucher or be excluded from future vouchers (as long as your HA is based in the UK).

If your wife gets her own card then, yes, she will get her own 2-4-1 which can be spent from the HA. Note that your wife must get her own card and NOT a supplementary card on your account.

(You can introduce your wife using the special offer on the Amex website, so you get 4,000 miles for introducing her and she gets 7,000 for joining!)