Kelly Osbourne and her fiancé Sid Wilson are reportedly experiencing a difficult time in their relationship, more than six months after Wilson proposed to Osbourne at her father's final concert. Since the death of Ozzy Osbourne in July, Osbourne has been traveling between England and Iowa, where she and Wilson live with their 3-year-old son on a 100-acre farm. A source tells PEOPLE that Osbourne's focus is on being there for her mother, Sharon, and Wilson's equally close relationship. This has led to a strain on the couple's relationship, which has reportedly been exacerbated by Ozzy's death. Osbourne posted a birthday post for Wilson on Jan. 20 and a Valentine's Day post for her and her son.