Insurance works by risk pooling. There is a small chance of your house burning down, but if it did you'd be paying out a six figure sum to rebuild it. So lots of people pay a small sum to an insurance company, and then the one person whose house does burn down is covered. The insurance company makes a profit (it's not a charity afterall), you get peace of mind for the sake of a couple of hundred quid a year, and the poor sod whose house burns down gets to rebuild it without going bankrupt.
To buy your insurance you pay a premium. The insurance company calculates the premium - the cost of rebuilding your house, times the risk of it burning down, plus profit and expenses (running their office). Their expertise is in calculating that risk. They'll compare you against other women, other homeowners, other people with your profession etc. They have huge data sets and are very very good at this.
With something like car insurance, the market is so packed that if they charge slightly too much, no one will buy the product and they won't make any profit. If they charge too little, they won't earn enough to cover the claims that are made and they'll make a loss.
If your marital status or occupation change, so does your risk of making a claim, which changes your premium. It's not personal, that's what their huge data sets are telling them. Different companies might use different risk weightings so it might change by less with some companies than others.
If, say, Company A thinks you become a bigger risk on divorce, but Company B thinks your risk reduces, then obviously on divorce you'll buy insurance from Company B. As will all the other divorced people. So Company B better have that right, or they're going to be in trouble. If Company A is wrong they're losing a lot of business to Company B.
This is a very long way of saying, don't take it personally. It's just the way the insurance industry operates working against you this time. It's probably worked in your favour at others (on your marriage, for example).