Thanks for your story; for me, it's not a unique one, and I'm wondering how anybody else could help you, if you can't help yourself?..
So you have felt in love with a beautiful Slavic girl (Slavic not slavish - pls note), 15 years younger than you. Not a miracle - Italians love Slavic girls; specifically, Russian girls. Natasha is not Latvian name. If she was/is living in Riga/Latvia, it doesn't mean she is "Latvian" girl, I mean, root Latvian. Also the age of your new passion describes you as a man who fells in love too often. Were you married earlier? having children? Most possibly YOU was the first serious choice of this young woman, may be the first serious relationship with an adult man, so SHE was also falling into passion with no strategical thinking. Young people nowadays are so adjective!
But are you really sure
afterall you have found the woman of your life? Or is it just a passion? Filming tango on streets stays far away from growing kids. And looking at your specialties, "music, photography"... are you sure these are professions the "clever" woman will hang up these days? It seems even in 42 you are still being a little kid in your soul, a little kid which needs instant playing and new toys each day. And "losing" Natasha, it seems like you were losing your new toy, and it seems unacceptable for you: "wtf? I was ALWAYS getting new toys with no problems, now the toy got me!"
Oh common, how many such "kids" I've met in my life, I know what you guys are about
I have a prediction that after meeting her (possibly OLDER) sister in Belgium, Natasha was brainwashed regarding Italian men and "husbands", because Internet is full of bad stories with agencies from Italy. I could expect that she's having a sick mother in Riga.
Usually, a person may avoid communication because of a deep depression happened recently. It seems like Natasha's life is not that rainbow-full and after getting even a small ray in the skies, she was attacked by her relatives to not make the next step, because it "may be dangerous" for her.
Wish you good luck in your research, but as you see, I'm truly skeptical about all that!