You don't wait 6 months to get married and there is no gigantic engagement party.
But that's not to say you can't have an engagement party.
Unless you ask them what actually happens, they won't tell you. And since you are still reading, I'll explain as best I can.
In Islamic law, a physical relationship is initiated with a marriage () to gain God's blessings.
Physical and deeper emotional attachments are a second or third aim, after this long-term commitment is made.
Please remember this whenever you're faced with a Muslim conundrum. Some Muslims outright say it 'I'm dating' and they are, in the complete boy-meets-girl-third-base sense. This entire dating culture of meeting someone for only sex, for only a short-term relationship, is not the ideal or healthiest way to go about finding a partner-in-crime.
Loving God and following His ultimate guidance is the sole reason and goal in Muslim belief. The more real answer is that yes, a lot of Muslims do. This type of dating to see if it's going anywhere or just stringing people along with heartache is not in Islamic law.