Here's the way it is. Your husband got married, he assumed the responsibility of providing for you. Which he does. He also assumed the responsibility of sharing in the raising of the children. Whether he's doing that is unclear - if he's leaving you with the whole load then yes, he's being unfair and needs to shape up his act.
Your husband also assumes the responsibility of caring for your emotional needs. Yes, he assumes the responsibility of listening to you talk about the kids for an hour or two if that's what it takes.
BUT WHEN A WOMAN GETS MARRIED SHE ALSO ASSUMES RESPONSIBILITY FOR SEEING TO IT THAT WITHIN REASON SHE MEETS HIS SEXUAL NEEDS, BECAUSE THAT IS THE MAIN THING HE GETS MARRIED FOR. Everything else a woman can give a man except sex, he could get a lot more easily - and cheaply - and with far fewer strings attached - by simply sharing an apartment with a male roommate. Companionship? Check. Friendship? Check. Someone to share the finances? Check. Someone to talk to (or better yet someone who WON'T spend all night talking when he's not in the mood for endless conversation? Check.
Your husband does fine on "two to three times a week?" That's reasonable, and not too much to ask. Considering he works eight hours plus per day for you...plus hopefully shares in the rearing of the children when he's home...it is the LEAST you can do to put out for him "two to three times a week." Put another way...how would you like it if he didn't talk to you and listen to your problems at least "two to three times a week?" Doesn't sound acceptable, does it? Well denying him sex is also equally unacceptable.
A woman who can't understand why "two to three times a week" is a perfectly reasonable request and a small price to pay for the benefits of being married is a woman who has no business getting married in the first place. None.