This is an interesting article in Entrepreneur which is US based but the tips here ring true for companies based in England and Wales as well.
The key thing is to plan ahead (pre/post nuptial agreements can be indispensable) and (as hard as it may be) try to keep your emotions in check for the sake of the business. Alternate dispute resolution (arbitration/ mediation / collaborative law) can also be an excellent forum for settling disputes over the family business.
Marriage always brings with it the hopes of "happily ever after." But once the fairy tale has devolved into the routine of everyday life, the fact remains that 50 percent to 55 percent of all first marriages end in divorce; the percentage is even higher for second marriages. While divorce is difficult for everyone, a fairy tale can become an absolute nightmare if the couple co-own a business. Then there are the employees to think about. When the co-owners talk about divorce, employees understandably worry and feel stressed about the future of the business and their jobs. So, if you're an owner involved in a divorce, think ahead. Laying a legal foundation and staying calm can make a stressful situation, while never pleasant, less traumatic than it would otherwise have been if both parties start shooting from the hip