Assalamu Alaykum Dear Sister,
Thank you so much for asking this question and for contacting Ask About Islam.
Simply put, Islam highly dignifies and protects women. Allah intends for women to be honored, respected and protected. He doesn’t intend for the woman to be the subject of a man’s fleeting whims and desires.
Accordingly, in Islam, relationships outside of marriage are not allowed given how unfair they are especially to the woman.
It is part of a woman’s honor and rights to have a marriage contract. This is a testimony from that man before The Creator Himself and all witnesses that this man will be responsible for taking care of the woman’s emotional, physical, spiritual, intellectual and financial needs. Any harm; emotionally, physically…..etc., that he afflicts on her is forbidden and he will be accountable for that on the Day of Judgement.
Alternatively, for a girl or a woman to submit her physical being and her feelings to someone who doesn’t owe her anything and can leave her at any point without providing her with her full rights, this is something that is unfair and unbefitting of women who are meant to be much more elevated than that.
If you think about this situation honestly and sincerely, the boyfriend can leave his girlfriend and chase after another girl freely as he pleases with no strings attached. This is abuse of girls’ rights. It is as though you open your house to a thief to come and steal what he wants and leave freely with no obligations or retributions whatsoever.
This whole situation deprives women of their rights and their sanctity. And Allah intends for women dignity and respect and that if a man desires her, then he has to act like a man and approach her family and announce that he wants to be with her and vow to protect her and give her all her rights— not to simply come and go through the back-doors.
I encourage you to read this article as well insha’Allah for more perspective on the subject: Sex before marriage?
To answer the second part of your question, of course a woman can love and be in a relationship. But this has to be a lawful relationship that gives both parties their full rights, a relationship that includes commitment, patience and mercy not just fulfillment of temporary infatuations and physical desires.
So marriage is what allows two loving people to start a dignified relationship together.
The Messenger of Allah (peace and blessings upon him) said:
“There is nothing like marriage, for two who love one another.” [Sunan Ibn Majah]
And remember that Allah Almighty is The One who created hearts and The One who controls hearts and if He wills, He can descend eternal love and peace and mercy upon the hearts of two people who wish to unite for the right intentions and for His sake.
I hope this helps answer your question.
Salam and please keep in touch.