If you can, try to see if you can optimize your route to avoid sketchy run-ins with motorists. When one road I took turned from a 4 road + bike lane in to a 2 lane no bike lane, I was frightened for my life, and fear is a powerful demotivator.
On the other hand, changing the route, waking early and getting the ride done despite achy legs and gasping lungs is very empowering. At the end of every ride, I relax and let myself soak in the badass feeling of what I just accomplished.
I also keep a running spreadsheet of how much I did vs how many times I wussed out.
At just starting out, there will be a point where the savings from riding a bike will surpass the cost of the bike and the net flow will be positive. Working to that tipping point is the first goal, and watching the gains stack up is the motivation.
Another goal would be biking more miles than driving the car (baby steps). The health benefits of exercise are decreasing a future speculative liability.
With that in mind, you might be pushed to overwork yourself physically beyond just the bike routine. Try to resist upping the fitness too much too quickly. Overworked muscles can sap away your will.