You have to have a financial settlement signed off by the judge. Its comes when the decree nisi comes through.
Covers all the assets, pensions, etc, etc.

If its am amicable break up then shouldn't be any bother, if its likely to go South then really don't buy anything just yet as she'll be entitled to half of it whilst your still married.

Been there, done it mate. My ex is decent enough we just got married to young and now want different things in life. But I've seen enough of it from other friends where the ex can turn into a greedy cash hungry biatch.

So whatever happens, just protect yourself.