M.L.
All I can say is that if you want to stop making excuses, stop making them.
Hey, that's real helpful, isn't it? :^)
But it's worth thinking about. That might be the first step for you to take. No excuses. You don't have to be heroic about it, but you can just stop thinking in that direction.
Excuses give you short-term ease, but it wears off quickly as you realize you should have been doing something that benefits you long-term. There will ALWAYS be excuses handy. ALWAYS. But you don't have to pay attention to them. You can recognize when a "reason" is an excuse and say no.
I can't tell you how to manage your time schedule. But when you decide on a time to work out tomorrow, that time is *only* for working out. Walking the dog burns calories, builds muscle, and helps your breathing (both for you and the dog), so that's great. That's part of your workout. Since you have decided to do something else as well, decide when and for how long. Even fifteen minutes at a time is better than none. During that time - let's say 3:30 to 3:45 or so - the house can wait, the laundry can wait, the dinner preparation can wait, the mail can wait, the computer can wait, and even the phone doesn't have to be answered. That time is for exercise and exercise only! Don't let anything persuade you it isn't! Once that time is up, you can pay attention to the other things you need to do. They'll wait for you.
Look at it this way: if you had to take medicine at certain times of the day in order to save your life, you wouldn't let anything stop you from taking that medicine at those times, right? No excuses. Do the same for exercise. It won't be a perfect arrangement, but it doesn't need to be. Concentrate on using the time you've dedicated each day until it gets to be a thought habit.
You can also help yourself by doing invisible workouts - taking the stairs instead of the escalator, parking at the far end of the lot, taking a walk at lunchtime (even in the corridors), anything that makes you move more. You don't have to put on a workout outfit to work out.