I believe the first wife should support her husband if he is led to marry yet another, at least in prayer in fasting.
It is best if the present wives are in harmony and unity with their husband if he seeks yet another wife, but that
is an EXTREMELY RARE occurrence. Wives are plagued by fears and insecurities, fear of losing their relationship with
their man, fear of being loved less, being less desired, less needed. With divorce and separation so common today
the temptation to feel insecure in the relationship is very real.
Personally I believe that the polygynist is extremely FOOLISH if he is NOT passionately committed to honoring the principles
of Ex 21, Prov 5 and 1 Cor 7
***21:10 If he takes ANOTHER WIFE to himself, her food, clothing, and conjugal privilege{5772} as a wife he shall not diminish.
[Strong's {5772} `ownah, o-naw'; meaning to dwell together; sexual (cohabitation): — duty of marriage.]
***7:2 but because of and to avoid sexual immorality each man should be [sexually] having his own woman, and each woman should be [sexually] having her own man. . . .4. The woman doesn't have [sexual] authority over her own body, but the husband [does]; in like manner also the man doesn't have [sexual] authority over his own body, but the woman [does]. 5 Do not be denying each other [sexually], unless, it may be, by consent for a time, that you may devote yourselves to fasting and prayer, and again be conjugally cohabiting [sexually reuniting], that Satan tempt you not because of your incontinence
******Prov. 5:18 Your fountain/genital should be blessed; and rejoice and be glad with the wife of your youth. 19 . . . her breasts should satisfy/intoxicate/saturate you at all times; you should be intoxicated continually with her [sexual] loving
If I were the wife of a Biblical polygynist and he was not totally committed to abiding by these principles, I would not trust him, would be greatly tempted to fear and insecurity, and would throw myself into fasting prayer for him and his desire. If he is a godly man and is committed to the principles in the Scriptures above, then the challenge to his current wives is to live according to
***Eph 4:1I therefore, a prisoner for the Lord, urge you to walk in a manner worthy of the calling to which you have been called, 2with all humility and gentleness, with patience, bearing with one another in love, 3eager to maintain the unity of the Spirit in the bond of peace.
My experience in seeking another wife has not followed any set path, other than calling on Jesus to lead me and guide me, trusting Him to work and will in me His work and will in the matter. Even to this day we have only the most tenuous hold on the Ephes 4:1-3 experience. My ladies have all had great difficulties with the "wives submit yourselves to your husbands in everything as unto the Lord" experience. As to the Eph 5:33 "the wife see that she respects her husband" principle, when they get disrespectful they find themselves talking either to my back or to an empty room. As to my Lady A, I was without a wife at the time and was sparrowing about seeking the wife that Jesus would provide, after I had committed myself to marry whoever He chose no matter how I felt about her. He miraculously brought us together and told her to marry me. Then there was Lady B who I met and befriended in a supermarket on a cold and rainy night, who said she would be my concubine, did not want to end my relationship with Lady A, after Lady A had kicked me out over an dispute re her kids. Then there was Lady C who I met at a supermarket with her kids, hired her to be my once a week housekeeper, and with whom I fell in love while still separated from Lady A, and separated by 120 miles from Lady B. Lady C said she would be my concubine, did not want to end my relationship with Lady A. Lady A had told me that she would divorce me in a year if I didn't measure up to her standards, and Lady C came on board with only 8 months left before Lady A's "D" day. I met Lady D walking on the side walk in El Centro in 110 degree temperatures, invited her to lunch. Two weeks later she accepted my luncheon invitation and months later she let me know she wanted to be my Lady. She readily and willingly committed to sharing me with Lady A when Lady A and I reconciled after five years of on again off again separation. Lady A accepts Lady D because she is such a godly and committed Christian lady. Both Lady A and Lady D don't like Lady C and want her to stay out of the pictures because she is spiritually such a loose cannon. Lady B wanted her privacy more than me and she bailed after five years. This is not the recommended way to seek and find another wife, but it certainly reflects real life.