There are two problems with his behavior.
As all too often with Republicans, there is the pursuit of power based on deceipt. A gay man found that by being a leader against gay equality, by furthering the deception as he married a woman, had four children with her, that he could get power. Forget the principles that he as a gay man 'had' to deceive about his sexual orietnation, be an Uncle Tom, to get elected. Forget him standing up for right instead of selling out. It's not just gays selling out gays, it's the middle class selling out the middle class, it's the selling out to the religious right, to the corporatocracy, all kinids of selling out of the public as well.
The second was his reckless, selfish act of driving drunk - something too many do, Republicans (remember George Bush), Democrats, celebrities, housewives, elderly and young, all over.
The test, though, is how voters weigh this against his political attributes.
For me, I strongly oppose drunk drivers, and would vote against most people over it, but I admit I'd vote for some people weighing their benefits as leaders above their terrible behavior.
If I were voting today, and it were Al Gore who had the drunk driving arrest and not Bush, I'd stil vote for Gore over Bush, because of the big benefits of his policies. I'd strongly condemn his behavior, though.
It's not an issue of 'liking him so forgetting his drunk driving', it's an issue of looking at the harm to the nationand the world of Bush and asking if putting him in office is justified over it.
I'd be a lot more likely to vote against anyone in a pimary over it, though. It'd be infuriating to vote for a candidate who did that. It's the same major irresponsibility for anyone however good they are on policy.
These tough choices come up. Who would not let Thomas Jefferson be President over his slave scandal? Who would not want JFK as president over his adultery? Some, but few I expect.