On the exercise front, think about walking. It is obviously inexpensive, and a great way to upgrade yourself physically. Try to get a walking partner (you might even become close friends with this person), and begin this exercise now – with the spring/early summer weather upon us. And adhere to a strict walking schedule, so as to gain its full benefits.
To boost your marriage, take a vacation with your husband – it does not have to be an inexpensive one. Take a day or two to do some fun things together. Hopefully, focusing on each other will give you the opportunity to rebuild your relationship.
You may also want to seek professional help from someone with a reputation for saving marriages. If your husband refuses to join you, you should attend alone and learn “countermoves.” Hopefully, these countermoves will ultimately lead him to go for therapy with you or to change for the better.
Hatzlachah in dealing with your challenging situation!