Ok I am almost in the opposite position in the form of how she wanted it. At the beginning of our relations 2.5 years, she could not get enough and we didn't have your problem, because I can never get enough of her. She would say things like I was the best lover she ever had etc, etc, etc....she was excited to be with me.... But over the last year she has come more and more withdrawn and NEVER initiates anything.
Things I used to do for her like Massage her body until she fell asleep now gets met with don't touch me. She turns away from me at night when she used to want to snuggle, if she ever kisses me it more of just a peck, no passion....it seems....but in her defense she is having major issues with her daughter, see my post in we're seperated.....
Now as for you wanting it more now, i kind of ran into the same thing with my ex. i was on this board when i was going thru the D.....The one thing Men feel strongly about is when a woman holds out sex, I prefer the words making love in a relationship to sex..... but anyway... When partners withhold intimacy, contact, or sexual contact.... It trigures something in our brain that says your are rejecting us.... and if rejected enough times we start to feel so rejected that we don't want to try, because we are scared of the rejection....
So how do you win this back..... At one point my ex wife was running around with all kinds of guys, while I was at home with the kids, or if I was at work she was still out running around....But the curious thing and its a place where I think you are at....Is if she felt i was going to leave or maybe start seeing someone she would get jealous and try to initiate sex with me, to try to hold me in the relationship. And I assume that is where he is at and the way he may be perceiving this.
You have to be very careful as to not come across as giving up these new sexual favors in hope of saving the relationship. Thats what it would come across like to me... As a male after being rejected for a number of years by someone you love, and her showing no interest... and then all of a sudden you are willing to do anything sexual to save the marriage, makes it seem like you feel all the problems were in regards to sex.... I am sure there are more issues than that.
I would consider if I were you, to find a sitter for the kids... Fix a nice Dinner, his favorite, unplugged the TV and when he comes home, have the dinner, and TALK.... About why your change in heart about Sex.... Ask him point blank whether there is someone else... Basically lay all your cards on the table, tell him why you felt insecure, ask him why is not interested.
Sex does not solve feelings of rejection that have been used over and over again, he needs to feel that there is love and intimacy left in the marriage on a daily basis not just when there is a crisis......