Girlfriend's best guy friend often stays in her house where I am not allowed to enter! What to do?

Friends I am in a difficult situation. I think you people can give me guidance. I am 37, Hindu and my Girlfriend is 26, Christian. We both are from Kerala (India). We both are living in Bangalore. I am a marketing manager and she is a dentist but not working. She was working in few clinics but salary for dentists is too low in Bangalore. I met my girlfriend 11 months back. She used to say sometimes she stay with her uncle and auntie’s house and sometimes in the rented house. She never gave me her address; she was telling me that if her uncle comes to know about our relationship then that will be a problem for her since we are from different religions. After 8 months I found that there is no uncle's house and she is staying in her rented house only where her male friend who is five years younger to her often visit and stay. She said that this male friend knows her sister and if he knows about our relationship he will inform her sister. Again sister might inform her parents about our relationship that may create issues for her. She is asking me to wait for another 2 years for the marriage. I told her that I can't continue this relationship but whenever I say break up or keep space with her she comes to patch up our relationship. She is telling me that I am not having modern attitude to accept a male friend. This drama is going on for 4 months. She is not leaving me nor allowing me to leave. She is still continuing the friendship with this guy. But I noticed that now a day this guy rarely stays there. She was asking me time to reduce his visit 4 months back. But still he is there. At present she is struggling with her career and education. Indeed there are lots of pressure on her about job and education. Still I am her main financial support to live in Bangalore and to pay her previous debts also. When I tell about the support I give her financially she says I am ‘counting’ the money I give and it’s irritating. She is asking me to let her solve the issues related job and education then she will solve the issue of this male friend. What is the best way to solve this issue? Help me. I have tried: 1. Tried to break up many times. 2. Switched off mobile/ not picked calls 3. Argued and fought with her many times 4. Beaten her for not meeting me on New Year but went with this best male friend for a movie (she said sister was there on New Year).