OK, you yourself can ONLY increase your benefit amount by working and earning more in at least one year, then you did in at least one of your existing top 35 years. Because your benefit is calculated off of your top 35 years (to derive a monthly average), you need to replace some of the lower of the 35 with higher earnings. That can be tough, depending. And requires to go back to work if you aren't already. You collected early, so remember you not only permanently reduced your rate by about 8%, but you forfeited the abilty to defer til age 70, which would have given you about a 40% boost just because you waited.
Your wife, on the other hand, IF it would get her a bigger benefit than a piece of yours (her spousal) can increase her OWN benefit by 16% if she is 68 even, and suspends her payments until she is 70. If she is more than 68, it will be some increase between 8 and 16% - and this is an option IF growing her own would cause her to have a bigger benefit than spousal. Since currently her spousal is her biggest, it tells me she did not work much in her lifetime - so, this also means that each year she does choose to work and pay those SS taxes, could result in a separate boost to her own benefit amount, because she will be replacing one or more zero years that currently make up her top 35 years of income, with an actually positive earnings amount.
SInce you are both young, and not disabled, working more and saving may also be a great way to increase available funds in later years when you actually are unable to work (if that happens).
I am sorry you didn't ask these questions before you both decided to collect early, reduced retirement benefits - the ability to defer collecting to grow your monthly amount is behind you, and nearly behind your wife, although as I noted, she has between 1 and 2 years to do so and may want to IF it is better than her spousal. But, you do have your health, so continuing to work is likely your mutual best option in order to grow your monthly income.