Married 4 years here, this October. Have 1 child- she's 9 months old.
Last Saturday Mrs VCH and I sat down after the little girl had gone to bed and had a "State of the Union" discussion together. With computers and the internet this is so easy. We pulled up all of our accounts- credit cards, banks, retirement, etc- and saw where we are, and our track with our current saving and spending and paying off debts.
Next we made a spreadsheet with things we have to spend money on, and things we want to spend money on. Now, having a child to provide for has really put things in perspective for us. But we're still not just parents. She likes to garden, wants chickens, and has other projects she wants to work on. I want to renovate the garage, work on project cars, and race.
Money sucks, yes, but it's really not tough, at least not to understand. Money coming in > Money going out, for a successful marriage, family, household, and life. Until they figure out a better way, this is how it works.
When we got married there was an adjustment period of figuring out the "we". After 2 or 3 years, it got easier. "Her" student loans and "My" credit card balance became "Our" debt to pay down. On December of 2014 we made our last credit card payment. In a few years, the student loans should be gone, too. Once we started looking at our debts as goals to overcome and not the shortcomings of the other person, joining together to vanquish them came easier.
Most marriages that fail, fail because of communication. Even when they fail (ostensibly) because of money, the real cause is lack of communication.
On your question: since it's for such a brief period, rent a car to get you through it. Don't try to rush and buy something just to have a car. Then after you're back to where you can ride everywhere, talk with her about your situation and figure out how to address it. You no longer have a company vehicle, so you need to start looking for something. You will likely need it, sooner or later, and she will understand that, as your situation has changed. Talk about it and figure out what you want to do.