My thoughts--committing to nursing is a calling and working in L&D is an even higher calling. Women's health probably is the greatest area of medicine where teaching is a huge factor in what we do. You never walk into the room of a laboring, antepartum, or postpartum patient without engaging in some kind of teaching.
If you can find the time to search around you can probably find scholarships
and grants--that would negate the issue of a second school loan to pay off. Pay for RN's is much better than teachers--so that's another way to counter your husband's objections. However, nurses training is demanding--you might contact reps of area schools that have programs and get a feel for what their programs are like--you might even ask to audit 1 or 2 classes or speak with instructors. You will need to have a solid understanding of what the clinical requirements will be because schools are not usually flexible for clinical rotations and this may interfere with your current job.
There are major concerns over the lack of students entering into the nursing profession and as a profession we are looking at an ever-worsening shortage, so you'd always be marketable and have a job.
Good luck making a decision--do you know any nurses or have any friends who know some nurses? I work with a nurse who used to be a high school English teacher (she's a fantastic nurse--it can be done!!!)