Get rid of your woman's "just friends" man/men. Fact of the matter, this is universal advice to all men.
Stop begging or arguing for sex.
Unnerstand this, make it clear in your actions, appearance, behavior, and ATTITUDE you will be just as happy and succesful as a good man without her as with her.
A woman, she is not impressed by ANY man that considers himself lucky to be with her. Consider instead she is the one in good position to be with such a good man as yourself.
Knock off the gift giving in general. Appreciate her giving you gifts or doing things for you, and if necessary, deliberately withold the usual compliments, "I love you's", "you look pretty's", until there is some reciprication beforehand.
(This may sound like a game, but REAL damage is being done to relationships when a man has the attitude he needs to bribe his woman, or worse, reward bad behavior as in this post.
Hypergamy is at the core of a woman's sexual attraction to a man.
At the THe core!!!
So good men reading this who are in shaky relationships, have GOT to get this in their actions and behaviors!)
Get the child out of the marriage bed, now.
"I don't feel like sex" = "I don't feel like sex WITH YOU".
Work on your attraction.
Read this: The Man Up and Nice Guy Reference
I wish you well.