I'm sorry I missed this. That is a great question! I know for myself, I keep up up the banter and passion and romance between them. I have most the conflict come from outside them (them against the world). With that said, sometimes there are a few speedbump especially if the relationship is new or in your case, the challenge of a child. But for me, the speedbumps aren't ever fatal. They're just opportunities for both to grow separate and together. Do you know the TV show Hart to Hart? It offers a great example of a passionate couple that stay interesting.