The same day Miley Cyrus Tweeted that she didn't call off her impending nuptials, she was spotted without her engagement ring.

Photographed outside of an L.A. recording studio late Wednesday night, the former Disney starlet, 20, tried to cover her face to avoid cameras, displaying two rings on her engagement finger that were not the bauble fiancé Liam Hemsworth gave her when he proposed last May.

Still, a source close to Cyrus – who has also been photographed without her engagement ring last month – insisted to PEOPLE on Thursday, 'Miley still wants to get married.'

But the relationship is not without its issues. Says the Cyrus source, 'Miley and Liam have had some problems that they are working through.'

The young couple 'have always had a very passionate relationship,' the source adds. 'They have a very strong physical attraction, but have very different personalities and backgrounds. This makes their relationship very complicated.'

Infidelity buzz and time apart have not helped matters.

'Miley is upset and angry about the cheating rumors,' says the source of talk that began in late February. 'Liam's trip to Australia was planned. He doesn't have a return date to Los Angeles yet.' .