For now, we know that Sarada is Sakura's daughter and Sasuke is the father. Leaving Karen as the deliverer. Sasuke at the beginning showed caring to Sakura for a long time.
Also since their married now, can we say that Sasuke even liked Karen? As many times as he had bitten her... I'd say if they even had a relationship that it wouldn't have been as strong as what he had with Sakura.
When Karin was introduced, she was shown to have feelings for Sasuke
It is confirmed in Karin's memory that she began to have feelings for Sasuke after he saved her during the second phase of the Chūnin Exam.
Tobi pointed out Karin to be Sasuke's "favourite".
Suigetsu pointed out Karin to be the girl Sasuke was "About to hook up with".
Kabuto pointed out Karin to be the girl Sasuke "knows quite well".
Karin blushed before being able to take a look at Sasuke after he saved her, which implies that was the first moment she started to like him.
The latter has saved one another numerous times
Karin is one of the people that Sasuke has apologized to
Orochimaru stated that Sasuke is "Karin's soft spot".
Karin stated that she "doesn't like anyone biting her, with the exception of Sasuke".
Karin stated that she only wanted Sasuke's happiness as well as forming a friendly relationship with Sakura and also delivering their child, Sarada.
Whether she still has romantic feelings for Sasuke is not confirmed, but the following lines she had stated "connections come in all forms" suggests that she still holds him in endearment, even if it's not romantic in nature.