We get stories like this almost every day. Yours is by no means the worst. Have you or she been snipped yet? Time to fix this for good.

Your wife actually sounds more responsive than the average woman raised in stupid religion, but you are pressuring her too much. You do not want her to think of stress+sleep deprivation when she thinks of sex. Frankly, you should probably masturbate more, not less, for the time being, and some occasional porn won't be the end of the world either. Does your wife mind if you take pics when she's wearing lingerie? You might also want to gently suggest that letting you see her naked doesn't have to lead to sex.

Honestly, this doesn't sound so bad. You and she will have a better life, in and out of the bedroom, when all the kids are in school. Hang in there.