Try not to sound nagging or bossy in any way, as this will backfire. If he agrees, leave small love notes with breakfast so your husband feels special. The more he associates feeling good with being on time for work, the more likely it is that he will want to keep to a schedule.
It is imperative that you tell him how you feel in a nice and loving manner and that the two of you together come up with a plan. If he feels that you think badly of him, he will only become insecure and get defensive; this will only make things worse!
I do not think that you should leave your husband, nor do I think that you should warn him that if he does not toe the line you will have to decide what to do. You say that you love your husband and you want to make it work, so please try again.
Along with working with your husband, you will need to change your frame of mind and be constructive. Make a list of all of your husband’s positive attributes and focus on reigniting your love for him and raising his self-esteem. Once he sees that you love him and are on his side, he will want to be successful for you and will probably try harder to have a good work environment. I wish you hatzlocha and encourage you to take the positive and supportive route!