I've watched some of their videos and I have always considered them to have a loving, but fun relationship. She is a feisty Argentinian and pokes fun at him a lot.
The elbow thing I hadn't seen before and that's concerning, but the being late one he just seems annoyed rather than anything more to me (my opinion).
As for the "why is she only just in the video" - they run consecutive lives on their Instagram so she is in half of his and he is in half of hers.
Don't know what to make of it all really.