Daisy may not love Tom all the time, in all situations and circumstances, but she does love him at times and she certainly loves the lifestyle his money allows her to have.
Daisy and Tom have apparently developed a relationship of coexistence that serves both of them in an advantageous manner. They each have their lover (Daisy with Gatsby, Tom with Myrtle) for excitement and passion; they have each other for social respectability - remember, divorce wasn't nearly as accepted in the 1920's as it is now - and for some measure of stability. There is comfort in familiarity, and they have found that situation. When Nick sees them through the window late in the evening of the accident,
Daisy and Tom were sitting opposite each other at the kitchen table...He was talking intently across the table at her, and in his earnestness his hand had fallen upon and covered her own. Once in a while she looked up at him and nodded in agreement. They weren't happy...and yet they weren't unhappy either. There was an unmistakable air of natural intimacy about the picture, and anybody would have said that they were conspiring together.
The conspiracy being developed, it would seem, was the plan to cut their connections with that place and those people, to flee the scene of Daisy's indiscretion and find another place to continue their self-centered lives.
They were careless people, Tom and Daisy-they smashed up things and creatures and then retreated back into their money or their vast carelessness, or whatever it was that kept them together, and let other people clean up the mess they had made...