Britney Spears wants to “repair” her relationship with her sons. The 40-year-old pop star is mother to Sean Preston, 17, and 16-year-old Jayden with ex-husband Kevin Federline, 44, but has become estranged from them in recent months and has reportedly stopped posting nude photos onto Instagram as part of a “concerted effort” to make amends. A source said: “Britney is now making a concerted effort to repair the relationship with her sons. She has refrained from posting what her friends call ‘racy’ photos and videos on her Instagram for two weeks. Although those around Britney think it is wonder…