Hmmm... not quite so...
I mean, in history he didn't ride to Ferrara JUST to see Lucrezia. By then he already conquered all the Papal States( so quasi everything what King Louis permitted him to) and started stealing up on Bologna and Toskana which Louis would never agree - in fact they paid Louis for his protection. At the time Louis returned to Italy to seize Milan once again and everyone whom Cesare had ever hurt immidiately run to the king complaining and hoping that Louis, who was very angry indeed, would finally kick Cesare's ass.
So Cesare rode to Lombardy asap to see the king and try to renew their old friendship. He stopped at Ferrara for virtually a couple of hours to see Lucrezia and pick up Alfonso d'Este( it was important for him to demostrate to Louis that Ferrara is still at his side and could be a buffer between Romagna and Venice). Then they both left for the french court in Milan and stayed there for a whole freaking month. It was pretty risky and Rodrigo thought Cesare is acting really stupid 'cause Louis could seize his son as a hostage in order to force him to support the French in the war in Naples.
But all went well so Cesare and Alfonso returned to Ferrara where Lucrezia had given birth to a stillborn child meanwhile. This time Cesare stayed with her a bit longer and that's when he held her foot and stuff.
I mean he surely worried about her and her health writing letters, sending the best doctors etc. But he never stopped his wars nor changed his plans because of her; it's just a myth that C/L shippers like to believe. I don't mind when people use it in fiction, though: it's beautiful.