Why do people sometimes say the boyfriend instead of my boyfriend? Is it slang native to a particular part of the country?
Most commonly I hear it used by people who generally say "my boyfriend" ("My boyfriend is from Chicago") but might say "the boyfriend" when they find themselves saying something stereotypically what someone would say about a boyfriend, e.g., "I got my hair cut today, hope the boyfriend likes it!" or "I think we're free on Friday, but I'll have to check with the boyfriend!"
This question about 'my wife' versus the slightly idiomatic 'the wife' is related.
Ok so let me answer this in easy way, my opinion is I use the boyfriend instead of my, why? Because I use my for objects that are MY property or pets and also family members because we are related blood like wise, but I hate saying my friends, my boyfriend, because it makes me feel that they are an object or they are MY property which is not right. They are free on whatever they want to do they are not MINE they can leave they can come so I just feel more comfortable saying "The" instead of MINE(my) I feel you give more respect towards that person freedom and dignity and it just sounds better in my opinion otherwise, hope this answer help your question, have a great day :)!