One is your husband's health. Another is his utter lack of attention to his weight gain. Yet another is the absence of communication in your relationship. Between the ages of 30 and 55, it's common for men to gain a pound a year. It sounds like your husband has quite surpassed this national average.
People overeat for a variety of reasons.
It could be that your husband is going through a mid-life crisis, or that he's bored and dissatisfied at work or with your marriage, he could be physically unwell, or it's possible that he's coping with feelings and emotions that he's trying to stuff down by eating. All or any of the above could be true. Instead of focusing on his weight, try to get a handle on what's going on in his life right now. You feel like you're not communicating any more and that you've grown apart. Know that men who are out of shape and overweight are less motivated to have sex.