And whoever of you have not the means wherewith to wed free, believing women, they may wed believing girls from among those (slaves) whom your right hands possess, and Allah has full knowledge about your Faith; you are one from another. Wed them with the permission of their own folk (guardians, Auliya' or masters) and give them their Mahr according to what is reasonable; they (the above said captive and slave-girls) should be chaste, not committing illegal sex, nor taking boy-friends. And after they have been taken in wedlock, if they commit illegal sexual intercourse, their punishment is half that for free (unmarried) women. This is for him among you who is afraid of being harmed in his religion or in his body; but it is better for you that you practise self-restraint, and Allah is Oft-Forgiving, Most Merciful. [An Nisa (woman) 4:25]
Clear cut statement that you can't have boyfriend or girlfriend. I can give another verse saying girlfriend is, not allowed if you need further proof? There is no ambiguity in Islam: what is haram is always haram regardless of time.
15) It is not for a believer, man or woman, when Allah and His Messenger have decreed a matter that they should have any option in their decision. And whoever disobeys Allah and His Messenger, he has indeed strayed into a plain error.
(Al-Ahzab, Chapter #33, Verse #36)
If you don't pay heed to verses of Allah today, Allah won't pay heed to you on Day of Resurrection. Hope that answers your question.