Though such types of desires are quiet common, you should not ask her for physical relationship. Because at 37 female would not look for physical fling but if she would, then she would look for emotional one. If she has an emotional fall for you then she may think of getting into it. Otherwise, you may loose your client and reputation, both. However if you wish, you can put foreword your wish smartly in disguise and see how she responds. I’m not touching the issue of morality as it is absolutely personal.