Britney Spears (44) makes serious accusations against her own parents. On X, the singer now accuses Lynne Spears (71) and Jamie Spears (74) of secretly taking trips with their two sons Sean Preston (20) and Jayden James (19) during the court order. For a whole summer, the grandparents went to the beach with the then still small boys – without informing the musician or involving her. In addition, she shares an old recording, on which her 20 and 1…