My husband and I have being married for 17 years he doesn't want to be intimate anymore because he says he is tired.
I have no idea whether he is cheating. It is possible he is tired. It is possible you both have left 'little' irritations (which often are a damaging as 'big' irritations) go unspoken so that over time your relationship has lost its 'spark'. It is possible he is in a midlife transition and mild depression.