The 26-year-old actor is having doubts about his decision to take back the brunette beauty after she cheated on him with 'Snow White and the Huntsman' director Rupert Sanders, and their relationship is currently very tense.
A source close to the couple explained: "The love story between Robert and Kristen is still a bit of a conundrum, it's a weird relationship. Despite claims that all is rosy - he's still not completely convinced that giving their relationship another chance is the right thing to do.
"For one, his family and friends are totally against the idea - and although he's his own man and makes his own decisions there are times when he thinks they are right.
"And there are moments when he continually asks her questions about the affair - so it's all still very tense - they have some really serious trust issues."
The 'Twilight' stars - who play star-crossed lovers Bella Swan and Edward Cullen in the cult vampire franchise - are hopeful their strong friendship can help rebuild their relationship and are focusing on keeping things platonic at the moment.
The insider added to RadarOnline: "They were brought together again by a great friendship so there could be hope. Robert thought Kristen was the girl he was going to marry.
"However, that's all on hold for the moment until they try and work things out. This could go either way."
The couple are said to have booked a holiday to a secluded Brazilian rainforest in an attempt to rekindle their romance.
They will be sleeping in separate beds under their $500 an hour therapist's orders, to "work on communicating, healing wounds and trust exercises."