The Rolling Stones guitarist has entered London's Priory clinic following his return from Ireland, where he had spent 10 days drinking with Russian waitress Ekaterina Ivanova, 20.
Friends of the 61-year-old say he is "infatuated" with Ekaterina - even planning to smuggle a mobile phone into the rehab facility so he can communicate with her - and his devastated wife Jo has left the country so she doesn't have to visit him.
A source said: "Ronnie's very mixed up at the moment. Alcohol has taken hold of his senses."
"He is totally smitten with Ekaterina and told her he was going to try and sneak a mobile phone into rehab so they could still be in contact with each other."
"Jo is distraught. She won't speak to Ronnie until he is sober."
Friends of Jo, 53, claim she has gone to Barcelona to "teach Ronnie a lesson" and "get her head straight."
Ronnie - who has previously been treated for alcoholism - returned to the UK from Ireland earlier this week after his son Jesse flew out to convince him to seek help.
A spokesperson confirmed he had entered a clinic for the seventh time, saying: "Following Ronnie's continued battle with alcohol, he has entered a period of rehab."
"His close family and friends say he is seeking help and look forward to his recovery."
It has also emerged that Ekaterina visited Ronnie the last time he was in rehab.
The rocker checked into the Priory clinic, London, last month after a wine tasting session prior to daughter Leah's wedding - and the young Russian visited him twice.
A source said: "Everyone thought this girl must have been Ronnie's daughter, but it quickly became apparent she wasn't. We then assumed she was a groupie."
Ekaterina reportedly left Ireland at the weekend, and according to her mom Irina, has now gone into hiding.
Ronnie met the part-time waitress during a night out in London.
