Kate Bivona and her husband don’t know what they would do if either gets seriously sick or injured. Until recently, that wasn’t the case. But beginning in January, the monthly cost of her Affordable Care Act insurance jumped by about $300 — making it too expensive for them to afford. Bivona and her husband dropped down to a bronze plan, cutting their bill by more than half but leaving them with an $18,000 annual deductible. “We would have to take out a loan,” said Bivona, a 37-year-old musician