Joe Jonas Filed for Divorce After Allegedly Catching Sophie Turner on Ring Camera

Joe Jonas saw/heard something with Sophie Turner that was the last straw in his decision to file for divorce, and it involves a ring camera.

Multiple sources who have direct contact with Joe tell TMZ ... Joe had access to a ring cam that he said captured Sophie saying and/or doing something that made him realize the marriage was over.

TMZ broke the story ... Joe and Sophie's marriage had been on the rocks for at least 6 months, and it was all over a significant difference in lifestyles. As one source put it, "She likes to party, he likes to stay at home. They have very different lifestyles."

As we reported, over the last 3 months, Joe has had the kids almost all the time. Sophie has been in London, but Joe and his bros were touring the U.S. and he had his 2 small kids in tow.

We know Joe had been in touch with at least 2 divorce lawyers last week. Interestingly, both lawyers are in L.A., yet he decided to file divorce docs Tuesday in Florida.

Joe and Sophie said in a joint statement Wednesday, "After four wonderful years of marriage we have mutually decided to amicably end our marriage. There are many speculative narratives as to why ..."

We reached out to Sophie's team ... they had no comment.