Being not very familiar with fantasy or mythology, I looked up possible mythological parallels Sea/Storm marriages. Since the founding of Storm’s End is a myth-type story in WoIaF, it could be inspired by some real-world myths. Found two:
1. In Norse Mythology, Ran (Sea goddess who causes storms to collect the drowned men) married to Aegir (the benevolent sea god). Both of them dwell in magnificent halls underneath the ocean (drowned god’s watery halls?). They have nine daughters who ‘personify characters of waves’ (wikipedia).
2. In Greek Mythology, Poseidon is the sea god. His daughter Cymopoleia, is goddess of giant storm waves. She is married to Briareos, a giant in return for his allegiance to olympian gods in the war against Titans. Judging by the wiki page most fantasy readers would already know about him. He was one of the Hekatonkheires who were children of Earth Goddes Gaia and Sky God Uranus. They were ‘figures of an archaic stage’ probably meaning they were older than olympian gods. The Hekatonkheires are said to have had a hundred hands for wielding clouds and fifty heads for blustering winds. For this, they were called Hundred-handers.
Now we enter tinfoil regime: Connections made using a murky collage of several god myths