I always thought that they just grew appart. Maybe the chatted when they met at the last jumping and we just don't have pics...
In any case, I am under the impression that Valentine is and has been for a long time an extraordinarily focused girl. She has persued her passion for jumping since she was a teenager, without the common breaks many teens take when they go to college, start adult life, etc. And she's very good at was she does but at the same time very level-headed and talks of herself as an amateur.
At the same time she's finished her studies, started work in the family business... without gap years, or tempations of taking up a socialite life! I think this is extraordinary for someone who so many options.
And she looks like a very interesting girl who really knows how to manage time. Not only is she focused and a good student and hard worker, she does surprising things and for a while she took part in several car rallies!
And she had such a fun and interesting fashion style...
I just want to clarify one thing. When we use the word "Hôtel" in french, it can have two meanings. It can be what everybody knows as a hotel, in english or any other language, but it can also mean a mansion or small palace. If we talk about Paris, the Louvre is a château, but they are also many big palace like residences who belonged to the nobility and rich people from the 15th century till the 19th century, that in english would be called palace or mansion, and in french are called "hôtel particulier", or just "hôtel" to make it shorter.
That's the case of the hôtel pozzo di borgo. It is not what in english is called a hotel, but a private mansion. I've google and it was built in 1707 and apparently it doesn't belong to the Pozzo di Borgo since the 19th century, so, after all, it's not that weird if Valentine wasn't at the VOgue party.