There's a bug I've noticed where you'll get an event to fall in love with your wife, and the game will consider it as cheating on your wife with your wife. Fortunately from what I've seen that doesn't mean your children will be bastards, but it is annoying when your player becomes guilty for "cheating" and gives you an event with no good options.
Anyway, after about 100 years I've managed to decimate the Andalusian emirates and form the Empire of Hispania! There are now just three independent powers in my De Jure empire, and I plan to take them all soon enough. After five holy wars in little more than a decade, two sheikdoms of the former Abbadid emirate is all that remains of the Muslim powers in Spain, and they will be conquered as soon as our truce expires. They didn't go without a fight, though. In the hands of a competent strategist they may have even turned the tides on me. Not only did they pull the nearby African Sultanates into the war, but each of them had an absurd amount of wealth to pay mercenaries. Fortunately I was able to obliterate the mercenaries before their morale built up.
The second independent realm is a single county held by the king of Bohemia. One of my sisters had matrilinealy married the heir to Bohemia and I had foolishly given him land. Later I found out Bohemia had seniority succession so the marriage was pointless. The county shouldn't put up much of a fight, and Bohemia is too far away to defend it.
Then there's Barcelona, just an independent duchy until recently. For years I left it to its own devices, thinking I could just vassalize it eventually. Then, while I tied up all the Muslim forces, they declared their own crusade to claim the island capital of one of the emirates. This gave them enough land to form the Kingdom of Aragon, and the new king isn't too keen on bending the knee. They'll probably take the longest to reign in.