Checking their phone
"In the world of online relationships, more and more people are obsessively checking their partners' history, messages, and social media posts," Lewis says.
"Unfortunately this is a double-edged sword." If you find something that looks suspicious, it's almost impossible to raise it with your partner - this means you need to reveal your snooping.
"You also usually don't have all the context, so it's easy to misinterpret what you're seeing. And if you find nothing, often you assume they're just being extra secretive, and the cycle continues," she says. "If you're having difficulty trusting your partner it's best to talk to them and work out strategies together to address this concern."
work out v. 做出；可以解决；设计出；计算出；锻炼；开采完；精疲力尽；发展，发挥
I believe that you can work out this problem by yourself.
We can find a way to work out this problem.
The police worked out a plan to catch the thief.