Before marriage, every man is Non-mahram for a girl(except close relations, and i hope you are aware of those relations). And Islam does NOT allows any type of intimacy, specially physical, with them.
Here is the list of Mahram in Quran:
"And marry not women whom your fathers married, except what has
already passed; indeed it was shameful and most hateful, and an evil
way. Forbidden to you (for marriage) are: your mothers, your
daughters, your sisters, your brother's daughters, your sister's
daughters, your foster mother who breastfed you, your foster sisters,
your wives' mothers, your stepdaughters under your guardianship, born
of your wives to whom you have gone in -but there is no sin on you if
you have not done so (to marry their daughters), the wives of your
sons who spring from your loins, and two sisters in wedlock at the
same time, except for what has already passed; verily Allah is
Oft-Forgiving, Most Merciful. " [4:22-23]
Coming to the point of Love, first thing it that you have stay away from Any type of close contact with non-mahram. If you still fall in love, it can be due to many reasons, but once you know that you actually LOVE (please not the difference between love and Likeness), Then Still he is not your mahram.. so all the rules of non-mahram applies to him.
Almighty said, (Say to the believing men to lower their gazes and
guard their chastity… And say to the believing women to lower their
gazes and guard their chastity and not to display their charms in
public.) (An-Nur 24: 30-31)
Allah Subhanahu WaTaala says in the Holy Qur’an, in Surah An-Noor: O
you who believe! Follow not the footsteps of Shaitan (Satan). And
whosoever follows the footsteps of Shaitan (Satan), then, verily he
commands Al-Fahsha (i.e. to commit indecency), and Al-Munkar
(disbelief and polytheism (i.e. to do evil and wicked deeds; to speak
or to do what is forbidden in Islam, etc.)). And had it not been for
the Grace of Allah and His Mercy on you, not one of you would ever
have been pure from sins. But Allah purifies (guides to Islam) whom He
wills, and Allah is All-Hearer, All-Knower. [Al-Qur’an 24:21]
Umar (RA) narrated that the Blessed Prophet (sallallahu alayhi
wasallam) said, “The man is never alone with a non-mahram woman but
the third of them is Shaytan.”
So in short, you love a man or not, he will still remain for you a non-mahram, you dont get any type of special type of allowed relationship with him, in case you love him or dont.
The best solution in this case, is to do nikah as soon as possible. Because once you are in love someone,then its like a goldern oppurtunity for Shatian to make each your close to each other by giving you many many logical reasons, like "You love him, its ok to come close to him its of to talk to him,its fine if you touch him, just dont do it much, just little",, and many such waswasaas....
so Beware of ticks of shaitan and stay away from him,till the nikah.