Software development is not an unreasonable start for certain chemistry-related careers these days. Developing analytical instrumentation and integrating it into existing lab management and document management software systems, molecular modeling, in silico biological system modeling, and various forms of bioengineering and chemical engineering are places where chemistry, math, and software come together, sometimes with disastrous results.
Since you already have a BS and some idea of what you are interested in, you might not need a BS in chemistry to get into grad school. What you will need is a few semesters of advanced chemistry courses, a graduate degree program that matches your needs, and a sympathetic research advisor that likes the idea of working across traditional boundaries. Find the type of research you are interested in, talk to the professor and show what you have to offer. You might be able to put together an advanced computer science/computational or analytical chemistry interdisciplinary MS or PhD. Your fiance may be able to help connect you with a professor that could support you as a research assistant while you were getting in the undergraduate hours you would need to apply to the grad school, and help support your application.