Ash-Shaykh Saalih al-Fawzaan, may Allaah preserve him, was asked this question:
Is it permissible for a woman to remain unmarried if a man who already has a wife and children seeks her hand in marriage due to the excuse that she wants an individual who is a virgin?
A: It is not permissible for a woman to remain unmarried, this is haraam upon her except if she has a legislated excuse because this (act ,not getting married causes the following):
1: It makes her lose out from (one of the biggest) opportunities of life (marriage).
2:Prevents her from having offspring.
3:This (reason) is the worse of (the reasons) which is this (act) exposes her to Fitnah and exposes her to fall into Faahishah, Fornication, because a woman is in need of a man no matter who she may be and no matter how she guards herself (from zinaa).So she is in need of a man due to what Allaah has given her of shawah (sexual desires), so this act exposes her to fitnah.
So if it is easy for her to get married to who she likes of a man who does not have (another) wife then it is okay. As for it is not easy then her getting married to a man who has a wife is a thousand times better then her remaining single where she is prevented from being married while it is not known that perhaps there is good in this (man) as a husband even though he has three wives, she can be the fourth. So the fact that she lives with women under the protection of a man who can keep her chaste, and causes her to give birth from him, while him being there for her assistance is better then her remaining single…
Reference: Ahkaam takhusul Marah, page:41-42, print: Ishbeeliyaa.