Re your claim:
I remember reading somewhere that the Allies (USA/UK) was not really keen on opening a second front to help the Soviet Union until the Soviets started to make progress in defeating Germany around 1942, 1943
Just the opposite was in fact true; the Western Allies were deathly afraid in 1942 that the Soviet Union might collapse (a la 1917) prior to their being able to open up a Second Front. Later, in 1943 and 1944, they were afraid that the Soviets might stop at the pre-war (ie 1940-1) borders and declare a truce with the Germans.
Both of these factors would stimulate the Western Allies to find ways to bleed off German resources in tertiary theatres, as they successfully did in Tunisia, Sicily, and Italy prior to the D-Day invasions of June 1944.
In The Last Lion - Defender of the Realm, Manchester and Reid note that at Casablanca Roosevelt said to Churchill that there would not be sufficient landing craft for a French invasion until Spring 1944. Admittedly this is partially a political decision, as once the Torch landings had been provisioned priority would shift to enabling offensive amphibious actions in the Pacific theatre for 12 months before shifting back to Europe. However even the immense economic engine of the U.S. had limitations, and took time to tool up and then produce the necessary machines of war.
However the additional time was probably required anyways. Early landings on the French North-West coast were problematic for the same reason that the Germans never seriously contemplated Sea Lion - amphibious landings in the face of determined opposition are difficult, and require extensive preparation. Without the Hobart Funnies that so eased landing on the British beaches Gold, Sword and Juno, and the Mulberry Harbours that enabled large-scale supply prior to capturing and clearing Cherbourg and Brest, the D-Day successes were far from guaranteed. All of these were developed in the 12 months leading up to June 1944.