Oaths & Vows

Does a promise constitute an oath?

Q: If one makes a promise by accident or something they don't want to say comes out of their mouth as a promise to Allah, does the promise have any effect? If a married woman says Allah, I promise not to have sex with anyone and thinks she also included her husband in this, has she promised not to have sex with her husband and will she be sinful to have sex with her husband?

What if a woman explicitly promises not to have sex with her husband by mentioning her husband in the promise. Will she be not allowed to have sex with her husband and will she be sinful for having sex with her husband? 

Taking an oath

Q: A girl said some words on the phone to her cousin (Irfan) in Ramadhan, sitting on prayer mat after salah. The words are "I never show my face to Khalid (cousin) and never try to meet him just let me talk to Khalid on phone call, if I did so, I will see my mother's dead body". Girl said that, its my oath or qasam. Now what she have to do if she wants to meet Khalid. Is there any kind of kaffara for it?

Breaking a vow

Q: One year ago I was caught up in a situation where I feared for my life. I kept lying about something to my perpetrators and then they asked me to keep my right hand on the Quran and make a vow. I vowed to tell the truth but again lied to them. I have repented to Allah for this wrong vow and I want to know how can I correct this.