Funny, alot of people here have accused MNetters as having double standards but if it were a women coming on here complaining that her husband doesn't want to have sex, we'd more likely get a fuller analysis of the situation... how many hours the man works, how demanding the kids are, does he do much round the house, she's not lost her baby weight, does he not fancy her anymore etc etc. This man has come across as extremely single-minded, numerous posters have asked for more background information to perhaps find an explanation for her unwillingness to have sex and he doesn't answer. I'll offer my own advice, she doesn't want sex anymore because,
a) She doesn't fancy you anymore, simple, she has a 'lovely size 8' figure but what do you look like? Are you fit and trim? Have you let yourself go? Maybe your time would be better spent down the gym rather than pestering her for sex.
b) She's knackered, two tots - needs no more explanation.
c) Do you take an active role in family life? Is she the one always entertaining the kids, taking them out? Does she provide all the affection to the children? Is she the one to always dish out the discipline? A good father is far more attractive than one who doesn't participate. I can't be arsed with my OH if he's being a lazy dad (ie. spending all weekend on the internet or watching tv).
d) You're too clingy and selfish. Many other posters have picked up on this attitude from you, which is more a likely reason for the abuse rather than a case of double standards. I'm 8 months pregnant and have a 2.5yr old, me and my OH have sex every few days, would probably be more if I wasn't pregnant. If he doesn't get it as much, he doesn't pester me or constantly touch me, we'd more likely joke about it. We love each very much but are not constantly kissing and cuddling like the early days, thats not real life. Surely after 18yrs, you must realise that your honeymoon days are well and truly over?
e) Sex is important in a relationship but its not the only thing. Companionship, the children, doing stuff as a family. Are you a nice companion and a good father? You mention that you do have sex, just not as much as you like, is that not normal after 18yrs? Maybe you're just creating a problem out of what is a entirely normal set-up for most people who are both working with two tots.
And going back to double standards, you come on here to get a female perpective, go on a mans forum, they will offer entirely different advice. If a female goes to a mans forum saying her husband won't have sex with her, they'd most likely say, "what size are you love? lose some weight", "get your hair done, its a mess", "maybe hes shagging someone else", "I'll sort you out, give us your number" etc. Not neccessarily what she wants to hear, but a mans perspective no less, get it?