Can I still stay here in the US if me and my boyfriend get married?
If your last etry into the US was lawful, i.e. after a passport check and stamp and everything, then you decide to marry while in the US, yes you can stay in the US legally. Although during the green card interview, you will be asked about the timeliness of this marriage, as your visa was refused recently. Be prepared to explain yourself. If you are marrying him just because of the green card benefit, you will be discovered and deported with no chance to raturn back to the US, not even as a tourist, for the rest of your life. Keep that in mind, before you decide what you want to do.