I'm still quite new at writing in the HP community so feedback is really quite lovely. (I suppose it feels lovely even when you've been writing a long time but I guess baby writers feel it more?)
I think SS/LM would be a more equal relationship in many ways than a lot of potential pairings for Severus. They are around the same age, have many of the same experiences and have a touch of the dark about both of them. I like to think that that stint in Azkaban knocked some sense into Lucius and then having his master break his wand cannot have endeared Voldemort to him... Also he is a smart man whose son is around Severus constantly. I think it highly likely that the Malfoys could figure out Severus' true allegiance and then protect him anyway.