My daughter is ~2 months shy of being 21. Her boyfriend is 46. For reference, I’m 45. She introduced him to my wife and me about half a year ago. Since then I’ve had to bond with him in order to maintain the great relationship I have with my daughter and also keep an eye out for her. But it’s tough, uncomfortable. It is what it is. As we say here “să fie ea sănătoasă” - as long as she’s healthy (health is the most important thing).