I think if people are emotional eaters, it often starts when they are very young so it's a long term behaviour. It might wax and wane but it's an established pattern of dealing with stress - self-soothing as someone said upthread. Often people do it for a long time unnoticed, until they reach a tipping point where they begin to gain weight. I binge ate intermittently through my teens but because I was thin it went unnoticed. Your husband probably overate for years but while he was sporty he was able to get away with it.
I agree with spare that the language that is used to describe overeaters is often incredibly value-laden. I know a lot of people who 'self-soothe' with a glass or two of wine a night but you'll never hear them described as 'lazy', 'disgusting', 'greedy'. In fact, Caitlin Moran has written about overeating being the addiction of choice for copers and responsible types, especially women. Self-soothing while still being able to do all the things that have to be done.
OP, you have every right to find your husband less attractive - that's absolutely fair enough. But look at it from his point of view. He knows he's overweight, he tries to make changes, then lapses. He fails, for a while, then he tries again. It's a cycle.
Your husband is using food as more than fuel. He's using it to cope with stress, to reward himself, to block other negative feelings and thoughts he probably can't even articulate ('God, I'm a big fat failure, look at the state of me, can't even stay on my diet, I bet they saw me sweating on the stairs in work today, I bet the missus doesn't even fancy me anymore.') And food is cheap and freely available and pleasurable and can make all the stress and boredom and tiredness disappear while it's going down your throat.
Your husband knows he is fat. He might laugh off comments but he knows. We all know. We're just not always sure what to do about it. For me, CBT and more awareness and compassion for myself is helping, slowly but surely. My binges are shorter now - a few days rather than weeks. Change is coming from me because I'm the only one it can come from.