I don't get aroused by my boyfriend anymore, because I'm too comfortable with him. Sounds weird, but I don't know how to say it differently. We've seen each other poop, fart in front of each other, we make ugly faces and weird noises for fun. There's nothing we don't know about the other one, nothing we haven't seen, and nothing we're embarassed about anymore. And all this took away the sexual tension for me. But I have no idea how to work on that, as I can't "unsee" things.