Why won't my husband shower so we can have sex?

A husband is a mechanic, comes home and wants sex, but doesn't want to shower...blames bad sex life on wife for YEARS. Lately, out of the blue..after years of not...he starts showering, but it's BEFORE work. He showers before work, then gets in the grease mechanics do...goes home, says he wants sex..isn't going to shower for sex with his wife, which you would think the logical thing to do. Then goes on about how he's not getting any sex from her, and blames her. If things are as simple as....you take a shower, you get sex, why won't he shower to have sex with her?