A little confused

I know, most of you are probably thinking confused is normal for me. Lol and usually it is, but this is different. I have someone that is very close to me, that says they are one of my best friends, but i have noticed a bit of a pattern that after talking it over with my best friend, Tanya, i have realized it is not in my head that it actually is odd. I can not figure out what thier deal is. Heres the thing, this person has alot of interest in whats going on in my life when it has to do with my kids, having a hard time, or a guy they know i cant be with but since stephen and I split this person seems to have no interest in knowing about any guy situation unless like i said its someone i cant be with. I know this may not make a lot of sense, i dont really know how to explain it like i want to. There was someone awhile back i was hoping something would develope with and they would change the subject any time i brought him up, at the time i thought it was just that specific person but it has happened again. If you tell someone that says they are your best friend that you met someone and spent the weekend with them, wouldnt you expect a reaction? questions or something? the response i got was ok and then they asked about my job. Do you see why i am confused here? what kind of best friend is not interested in something that would make you happy?