I don't think this is correct. I've gone through this process with a solicitor a few years ago. Joint tenants is typically what married couples do, so all split equally. If you are tenants in common, you can specify ownership percentages for a purchase. So if one party significantly contributed more, it can be 60/40 or 80/20 or anything you like. In your will you can then separately specify, how your share gets treated independently of the other party.When you bought your current house did you own it 50/50 Joint tenants (or some other split) or are you tenants in common (both owning 100%)
It gets a little muddy if then the owners marry or form a civil partnership, as a marriage CAN override this percentages depending on circumstances. Proving that over the years both equally enjoyed living in the house etc. Solicitor can add language to take this into account. Whether it will stand up in court.. no clue.
In either case, having one done is better than nothing. Nothing = Intestacy Rules. It can lead to weird situations where if there is a a fatal accident of a family and one person dies a few seconds after another, all gets move to one side, rather than equally split... Best to be in control (as much as one can) for these scenarios...
And one other thing to add, a will can be amended at any time. So if you feel your life situation changed, you can make changes to make sure this gets reflected. e.g. relationship breaking down or new children being brought in.
