Cheating IS wrong, but, man or woman, physical abuse is worse.
I was also really glad to see Clint stop her firmly when she tried to strike him again. Infidelity is not an excuse for domestic violence, regardless of the target.
One thing that I liked about this scene is that Jess goes in for a third hit and Clint grabs her wrist and says something along the lines of “I know you’re angry, but you don’t get to do that”. I thought it was really, really great for violence as an expression of emotion to be called out within the text. And I remember thinking at the time that the word choice was very considered and precise, which I think implies a lot about Clint and his own background with violence (Clint’s abusive parents - fanon, canon, or ‘depends who’s writing him’?).