I find you need to make exercise a habit, when I first started swimming 10 years ago, I hated getting up early and if the water was a bit fresh, but I made it the only thing I had to do on those days. Once you meet a few other regulars it suddenly becomes something you cannot live without, I swim all year round and if I cannot swim I get quite upset. Same with my afternoon walks and listening to music, I walk the other 3 days in the arvo but each day is a differnet spot/route, grab yourself some good shoes and ear buds and nice cool sports clothes and work out a walk for the amount of time you have available.
Suddenly in goes from being exercise to lifestyle, and you cannot live without it. Never give in !