There may be different views as to whether a male (or female|) MP having an extra-marital affair is grounds for marking them down. I feel that if the same rule were applied to the general population then quite a lot of people would be deemed unfit to enter politics. If, however, I knew that a politician had behaved extremely badly towards their spouse and/or the person with whom they were having an affair (such as in the Cecil Parkinson case), this would affect my view of them. I don't see why offering support to a woman who decides to have an abortion is a bad thing - unless "offering support" is a euphemism for applying pressure.
If I were a Conservative, I wouldn't need to look at BJ's slightly tawdry personal life to come to the conclusion that I would not like him to be a leader. His record of broken pledges and questionable deals would be enough to put me off.