It sounds like you live in a standard size house, so a large bathroom with room for a free-standing bath and a separate shower is a luxury, but if it is a luxury that you want and are prepared to pay for, go ahead, once you are prepared for the downside.
It will reduce the attractiveness of your house to potential buyers. Very few houses only have one bathroom and no ensuite these days and it is seen as an essential by a lot of people.
If you have one child and another one hopefully in the next few years, then 10 years from now, you will find two bathrooms very useful, and will be frustrated by only one bathroom ( I am that soldier and cant wait to get a second one built very soon).
But that is 10 years away, and you say that selling the house is 10 years away, so if you want to spend the money to have a better house to suit you for the next 10 years go ahead.