What prevented Odysseus from coming home after the Trojan war

The Achaeans spent ten years fighting Troy. Thanks to the valor of Achilles and the cunning of Odysseus, they succeeded. However, many of the heroes were fated to never return to their homes. On his part, Odysseus endured a number of trials which lengthened his return journey by another decade. 

First, the Greeks angered the gods by violating the Trojan temples. Thus they shipwrecked many of the Greeks. Twice more Odysseus incurred the gods' wrath....

The Achaeans spent ten years fighting Troy. Thanks to the valor of Achilles and the cunning of Odysseus, they succeeded. However, many of the heroes were fated to never return to their homes. On his part, Odysseus endured a number of trials which lengthened his return journey by another decade. 

First, the Greeks angered the gods by violating the Trojan temples. Thus they shipwrecked many of the Greeks. Twice more Odysseus incurred the gods' wrath. First, he killed Poseidon's son, Polyphemus the cyclops. Second, his men ate the sacred cattle of the sun-god Helios; Zeus responded to this affront by shipwrecking Odysseus on Ogygia. Odysseus remained on this island for seven years, imprisoned by the goddess Calypso (by this point, all Odysseus' ships had been destroyed and all his men had died). Finally, Athena convinced Zeus to free him.

Odysseus, was also--at times--delayed by his own infidelity. For example, Odysseus spent a year with the goddess Circe.

Despite these trials, Odysseus finally made it home to Ithaca and his family (his wife, Penelope, and son, Telemachus).