Will someone help me please (i'm desperate) :-)?

a few days ago i posted a question about my boyfriend and his female friend. I didn't notice i left some things out. My boyfriend call his female friend everyday and all day. Sometimes she don't answer, he'll leave a message. She return his calls. He would always call her on his cell and go outside when i'm around. Sometimes he may call her on the house phone when I'm not around. On thursday night, I can't remember if she called him or he called her. He told me that she ask for $20. for her daughter birthday. That was about the 2nd time he came to me about what she asked for. I told him don't give it to her. For the simple fact that every time I ask for money he gives me a sermon about him paying his insurances, fees to get his license back, and community services. He still gives me the money, but it won't be the amount I asked for. He didn't even contribute on his son birthday last year. I was the one who gave his son like a mini birthday party. I cooked toastadas (that's what he wanted) and baked a chocolate cake with hershey kisses on it. He's not even my son. That's his son from a previous relationship. I don't know if he gave it to her or what (the $20). I think friday or saturday night he had called her again (even though he had talked to her like 3-5 times that day maybe even more). He was leaving her a message. I couldn't really hear what he was saying. He was talking real low in the next room. I heard him say he's going to bed he was saying other things but i couldn't hear. I have a best friend and I don't call her as much they call each other. I have male friends I don't even call them like that. I call them like once a month. I have respect for our relationship. He even lied to me once about talking to her. He told me he was talking to his niece. I confronted him about it. He said he made a mistake. That he didn't meant to say his niece. I want to confront him about talking to her everyday and all day and why he always have to leave out the room when he talks to her. Every time when i talk to my friends, I talk to them right there in front of him. Every time I express on how i feel about a situation and confront him on things. He gets all defensive and yelling. I come at him at a respectful tone, I don't yell, and I don't come at him all crazy. I always ask him why is he getting all defensive and yelling. What can i do.