No one asked her because, first, that would be slightly inappropriate to ask her out of the blue who she’s dating and then because we actually don’t know how she mentioned it and we can’t even be sure she did. The first time, when she said “If I didn’t have children and if I was single”, the article was rewritten so we’re not even sure it’s her exact words. Then, with “my partners have been British”, it doesn’t mean they still are, so no need for the journalist to ask who he is and once again, the article was rewritten and badly translated, so we don’t know what she really said.
The only times we know the context she mentioned her “partner” in were under the London Eye when the journalist asked her and Jennifer about their partners, and Gillian didn’t look comfortable at all taking about that and skipped the question as fast as possible. The second time was when she said “my partner” talking about David on this radio interview.
In other words, I’m really not worried about all that, everything she has said on this matter lately is subject to interpretation and one see what they want to see. I see nothing worrying 🙂