I know what you mean, Fedorahead. The awkwardness of the kiss and the wedding was very much realized as pointed out by Forbidden Eye, but could have been totally avoided.
Too bad Spalko didn't follow up in her attempt to lure Indy off the beaten Ravenwood path. They had a thing for one another, especially Spalko. The knee touching in the tent near Akator could have developed into much more and sealed the deal, and ultimately Spalko's fate. At that point, Spalko knew she had Ravenwood captive in the other tent and she knew of her previous relationship with Indy based off Red Army intelligence reports. She moved in for the kill. Unfortunately, Indy couldn't be bothered by the attempt as looking into the Skull moments later turned his emotions into nothing and caused him temporary amnesia. He completely lost recollection of the knee touching. To the space between spaces with everything! This was her undoing. He most certainly would have ran away with her and would have ditched Marion and the wedding altogether if the scene was played out as intended. Mutt would just have to deal with it as he did with the "his father joining up with the RAF" gaffe. Eventually, Marion would find comfort(and revenge?) in the arms of Sallah. Remember the kiss(es) in front of Katanga and Indy in Raiders? She never forgot about that or the singing that followed. This would have all been key in ensuring that Indy returns single for Indy V, regardless of his age. He could never be tied to Spalko in any way as he could with Marion(Mutt). It would also have been a good way to have Mutt distance himself(traumatically) from Indy as to not appear in Indy V or beyond. It is the ultimate Indy lady's man scenario that never came to the forefront in KOTCS, sadly.