Re: Game of Thrones BOOKS – Spoilers!!
After rexamining all the evidence, I now agree with you.
It seems that:
Rhaegar and Elia had an unhappy marriage - proof is that he named Lyanna as queen of beauty at the Tourney instead of his own wife.
Rhaegar and Lyanna ran off together as a result. Lyanna’s father was incensed at this as he had promised her to Robert.
Robert’s Rebellion took place as a result of the Aerys’s reaction to these accusations.
At the end of the rebellion, (so many months later, maybe even 9 months later…) Ned finds Lyanna dying in a bed of blood (such as what would be there after a difficult childbirth) defended by the Kingsguard.
Lyanna makes Ned a promise… protecting the identity of her baby would be a good promise, as she would know that being the last Targaryen in Westeros, his existence would be a challenge to Robert. She would probably already have heard of the slaughter of Elia’s babies and fear the same for her own.
It is extremely unlikely that Ned would father a bar steward, as Robert teased Ned for staying loyal to his wife throughout their rebellion while Robert frequented whores.