I have a simple rule that I apply to myself. If my SO were hear, reading what I am writing, seeing what I am doing, listening to the conversation, would I be doing it? Would I give a woman a passionate kiss in front of my SO? No. Therefore, I wouldn't do it.
Having said that, I have come to understand that addiction is also a disease of selfishness. The addict does not think about how their actions affect others. That selfishness does not go away the moment they enter rehab. In many ways, recovery in the early stages tells them to be selfish... to place their recovery in front of everything else. The first 7 steps are in many ways all inward looking. It isn't until step 8 that they confront the impact of their actions on the world.
I also read somewhere that for people in recovery, having starting a romantic relationship is a way of reducing the need to have a relationship with your Higher Power. It makes the person feel loved / special... but is simple outside validation... not an acceptance (from a Christian POV), that you are loved, simply because you are a child of God.