If they are very 'stuck in the mud' with their attitudes towards improving their business practices, then I think you also need to think about the longer term impact on your career.

Yes, you might want to work for them long term, because at the moment, you feel you need the stability and security because of your husband and child.

But you need to bear in mind that if your circumstances change, if you need to move to another country with your spouse and get a job elsewhere, then your business practices will be really out of date, you not only won't have been using modern accounting software, but also, you won't have learned any new advances either, which come along from now, over the next few years.

Once you start working for that company, it would be quite difficult for you to move on to a different job in a different company, I think, because you won't be able to develop and improve your skills in the same way you have been doing. To my mind, it could potentially have an adverse effect on your resume in the long term and your longer term career options.

And to me, you sound like you enjoy your current job, you seem like a progressive person who lives a new challenge, to learn new things (maybe also a reason why you're considering this new job). Given your progressive and modern attitude, would you really be suited to working in such a backwards environment as the other antiquated company?

Are there any opportunities for promotion where you are working now? Maybe you could earn a higher salary in the company where you are working now if you got promoted?