Spears began dating Trawick in 2009 before announcing their engagement in December 2011.
Trawick famously appeared alongside Spears in the music video for her 2011 single 'Criminal'.
In 2004, Britney tied the knot with childhood pal Jason Alexander on a whim; the marriage was annulled 55 hours later.
Jason has been very stressed and concerned for Britney and what she might do if he left," the insider said.
"He is worried about her and really loved her, but it started to take a real toll on him.
Her "bizarre" behavior led to her estranging herself from her parents, who soon after realized she was abusing drugs, Gladstone continued in court today.
Britney's whirlwind marriage to backup dancer Kevin Federline later that year actually came as a relief to Jamie, who looked at it as the beginning of a calm period in which the beleaguered star also had her two sons, Gladstone said.