Since you been doing matches, if Stannis or Renly had been the eldest Baratheon brother do you think think Lyanna would still run? Stannis has no bastards, cold as the wall, but honorable to a fault. Renly you get all the courtly grace even if the bedding is infrequent but still no bastards. Both would have honored Lyanna.
There really has been lots of matchmaking lately! It’s fun.
This kind of touches on a topic that I’m interested in and have never quite felt like I had a good way into, so I’m going to give my kind of overarching theory for why I think Lyanna ran. (Note that all of this is IF Lyanna did elope with Rhaegar. I happen to think there’s a fair amount of evidence supporting that belief and very little suggesting otherwise, but I’m uncomfortable not acknowledging the possibility that she was abducted.) I really doubt that it was just about Robert.
“You have a wildness in you, child. ‘The wolf blood,’ my father used to call it. Lyanna had a touch of it, and my brother Brandon more than a touch…Lyanna might have carried a sword, if my lord father had allowed it. You remind me of her sometimes.” (AGOT, Arya II)
Now two children danced across the godswood, hooting at one another as they dueled with broken branches. The girl was the older and taller of the two. Arya! Bran thought eagerly, as he watched her leap up onto a rock and cut at the boy. But that couldn’t be right. If the girl was Arya, the boy was Bran himself, and he had never worn his hair so long. And Arya never beat me playing swords, the way that girl is beating him. She slashed the boy across his thigh, so hard that his leg went out from under him and he fell into the pool and began to splash and shout. “You be quiet, stupid,” the girl said, tossing her own branch aside. “It’s just water. Do you want Old Nan to hear and run tell Father?” (ADWD, Bran III)
She wasn’t just running away from Robert and his cheating. She was also rebelling, partly with the cause of resisting her father’s choice to break from what appears to be the venerated First Man tradition (still grossly patriarchal but with at least the autonomy to learn how to protect herself and not so much emphasis on conventional femininity) and box her into a southron ladyship so that she’s a valuable export to Storm’s End. I wouldn’t blame her if she wanted to rebel against that and she was going to want out of any marriage that would only have her on those terms. But I suspect there was more to it than that.