I used to feel this way all the time. I understand exactly what you mean about feeling vulnerable. Also for me, I think my reaction was partially based on a misconception that men always want sex and for him to turn me down means that there must be something wrong with me. It's taken me quite some time to get over that and the rejection still stings sometimes. But, my husband works hard and is really tired when he gets home. He often doesn't get enough sleep. So, really... I can understand why his sex drive just isn't as high as mine. When he does turn me down, I think about those mood killers in his life and it's easier for me to get over that knee-jerk reaction of 'What's wrong with me?'. Sometimes my husband just wants to cuddle and there is nothing wrong with that. =)