All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
To begin with, may Allah reward you for being keen on raising your children and caring for them.
Our answer to your question, whether a woman can get married on condition that there will not be coitus, is that for a woman to set a condition for her husband that he must not have sexual intercourse with her, then this is an abrogation to the marriage contract. This is so, because this condition is in contradiction to the purpose of the marriage contract that basically involves sexual enjoyment. So, marriage will be invalid with such a condition.
We would like to draw your attention that if you mean by this condition to keep your first husband as your husband in Paradise, then we tell you that by just legally making the second marriage contract you will have a second husband even if he does not have sexual intercourse with you.
As to which husband will the wife be in Paradise – the latter or the better in terms of piety and morality – then the preponderant opinion is that she will be left to choose the best in terms of moral and religious aspects.
This is based on the Hadeeth reported by Ad-Daaraqutni from Um Salamah, may Allaah be pleased on her, who said to the Prophet : “In case a woman is married to two husbands in this life, then she and her both husbands die, so to whom she will be in the Last Day (Paradise)?" He said: “To the one who is morally (religiously) better. O Um Salamah! Good disposition (piety) is to win the favor of both this worldly life and the Hereafter.” This Hadeeth was also narrated from Um Habeebah .
So, this intention must not prevent you from getting married to another husband so as to protect yourself and your children.
Allah knows best.