This is why doing a short exercise routine at home before work makes so much sense. It doesn't have to be ALL or NOTHING. If you simply get up 30 minutes earlier in the morning you can fit in a short workout at home. There is no driving time and you were going to shower before work anyway.
You are probably saying "I can't get up 30 minutes earlier". However, getting up a bit earlier is just a matter of changing your priorities and changing your habits. Starting out you will have to do some planning to get to bed on time. Think ahead and have your morning routine streamlined. Over time it will become a habit, your routine, and you may even miss workouts when you skip.
If you do have time to get to the gym once or twice a week you can still supplement that routine and become much more fit by working out at home the other days.
Implementing a healthy lifestyle is mostly about changing your habits. Don't sell yourself short by doing nothing because you can't do everything!