Salam Dear Sister,
Thank you for your question and for contacting Ask About Islam.
It gives me much pleasure to answer your interesting question.
We would like to thank you for your concern about new female converts to Islam. For sure, Allah the Almighty in His infinite mercy and wisdom will not let the new sisters down. He will make a way out for them from every difficulty they face in their transitional period after taking the shahadah. This is because they have taken the decision to embrace Islam which Allah has chosen for people.
As for the issue of suggesting a second wife to your husband, it is a personal decision you can take.
In the story of prophet Ibrahim (peace be upon him) we have a precedent. Lady Sarah and Prophet Abraham (peace be upon him) remained childless despite the divine promise that he would be granted a child. The gifting of a handmaid by woman to her husband in order to produce offspring was a common practice at that time. Therefore, Sarah suggested to prophet Ibrahim that he takes Hagar as his wife.
Having a second wife is an option in Islam. It is not the sixth pillar of Islam. Those who take second wives are not better than those who are happy with one wife.
If you will be happy with being a second wife, there is nothing wrong with suggesting a second wife for your husband to guarantee a good life for a new female convert to Islam. For sure, there will be a great reward for you because of your concern about female converts.
You will be rewarded
also if you treat the second wife kindly. You will also be greatly rewarded if you manage the feeling of jealousy of the second wife.
If you feel that your life will be badly affected by being a second wife, give up the idea of suggesting a second wife for your husband. As for female converts, Allah will help them and facilitate their marriage issue.
Generally speaking, as soon as they convert, new female will receive many marriage proposals from many people. Muslim leaders will tell them that marriage is half of the religion, therefore, they have to marry. Also they may marry the men they knew before their conversion to Islam.
Some of new female converts will marry because this would be the best way to learn more about their new lifestyle and Islam. Few of them will marry in order to escape family pressures after conversion.
There are many good practicing Muslims who are ready to marry new female converts.
I hope this answers your question.