How about a father and son for that matter?

No thanks...too weird.

wife-in-law (plural wives-in-law)

1. A wife in law only, such as one who has abandoned her husband
2. A wife who provides domestic or social support, but not love or affection
3. Another wife of one's husband. Typically used in cases of divorce and subsequent remarriage.

co-wife (plural co-wives)

1. In a polygamous marriage, another wife of a woman's husband.

co-in-law (plural co-in-laws)

1. (rare) A distant in-law: A relationship by marriage with a separation by three degrees (two people), compared to prototypical in-laws, where the separation is two/one. The separation may be two degrees of blood kin and one of marriage (addressing the mother of the husband of one's daughter) or one degree blood and two of marriage (addressing the wife of the brother of one's husband).

Hmmm.

I can't even keep one woman happy. You people impress me. But then I am impressionable anyway.