My kissing gourami and blue/three spot gourami?

No, they cannot interbreed. Not only are they not the same species (Kissing Gourami= temminckii, Blue Gourami= trichopterus), they are not even in the same genus (Kissing= Helostoma, Blue= Trichopterus), making them not nearly as closely related as Blue, Pearl, Snakeskin, and Moonlight Gouramis (T. trichopterus, T. leerii, T. pectoralis, T. microlepis, respectively). The kisses you're seeing are most likely small battles for dominance, which will continue until one wins. If you have a 40+ gallon tank, it should be fine, as the loser will have space to retreat (and the Kissing Gourami will have room to reach its adult size of around 8").