I think something might have sparked between them when they were in the frozen forest on the way back and Aethelwulf put his cloak around Kwenthrith and her son.
Aethelwulf has been played badly by his father and his wife over Athelstan. Now he is involved with the mother of one of Ragnar's children, and Ragnar is also a huge fan of Athelstan.
It is interesting that Ragnar's ex-shield maiden wife, Lagethera, is having relations with the guy who swears he desires and loves her, not just wants her power, while he conspires with the young man seeking revenge on Ragnar by destroying all of his family. Justapose that with Aethelwulf and the conflict he has with all those who love Athelstan, it could get interesting. All these people are tied together in some very complicated ways.
Poor Helga. She gets the worst of it and she is probably the kindest of the bunch.
Think Rollo is about to go back to being Rollo something fierce. He'll probably save Gisla from Count Odo and that couple who are conspiring against her. She may not love her Viking savage hero then, but she may come to rely on him. He is destined to rule and leave an heir.
I want to see how Bjorn handles the Beserker coming for him. Bjorn Ironside is formidable but a Beserker is something else. Still, Bjorn took on that bear with a knife and an axe, he is battle experienced, and he is Ragnar's son.
It will be interesting to see if they all come together again to save Ragnar, or Bjorn, or Rollo, or Lagertha when all the negative forces converge on one of them.