well junestarlit...you have a problem on your hands (duh?? right)

so you have tried to talk to your bf & he is not getting it. you may have to try the "blunt stick" approach! LOL! you have got to be a lil more a matter of fact...you are not getting your needs met and it is an issue. in a relationship both partners are responsible for taking care of each other's needs.period.
there is no excuse for him to be withholding sex from you...sex is a very, very important part of a relationship and all partners involved need to be on the same page or there is going to be trouble.

when i am dating i make it a point to let any perspective gf know upfront that i have a high sex drive and that stops any misunderstandings early on, everyone is different but these are topics that need to come up when someone is dating..but all too often people don't want to touch the subject for fear of running people away.

there are things you want done(going down,etc) and it's not happening.
this is a real problem that needs to be fixed. your satisfaction as well as his is very important or it won't work..simple as that. IMHO it is never "too late" or "too early" or "too hot" or "too cold" to have sex..these are BS excuses..nothing more, simply an attempt to get out of it that's all & it is not fair to you.

i get the impression your bf is selfish and irresponsible..i suggest you start becoming more independent, it can't be all about HIM and pfft on you, a relationship is a 2 way street..teamwork, the idea is to work together on all endeavors, he doesn't want to do it...it's time for a change.

he needs to be told( nicely not yelling or screaming) that you are not satisfied with how things are and you will not continue to be unhappy, again a relationship is about balance & fairness..one person can't do all the work, he starts helping or you move on!

i hope this helps & you guys can work things out!