that 's not to say i have n't thought about it - i 'm only human - but until the night of the office celebration , the idea of cheating on vanessa had seemed so far from possible , let alone likely , that even as i held tina 's slim , hard body to me , as her hands burrowed urgently down the front of my trousers , some part of me wanted to laugh out loud at the ridiculous idea that it was happening at all .