It is not a bad idea to have them help you. It is not bad idea to have them help you with a diet, either.
It is a bad idea to confess to them as if one is confessing to a priest. It is a bad idea, for example, to have a spouse play the role of spiritual advisor, because that person is so close to you that the spouse cannot be NON-OBJECTIVE. It is also a bad idea to have a spouse who is a physician treat the other spouse, and it is a bad idea to have a spouse use the other as a coach, such as for dieting. Your sins are your own. YOU did them, not your spouse.
And yes, laziness is a sin, although usually a venial one.
Finally, NOT EVERYBODY IS THE SAME. If you think you can go to confession with your spouse, or treat your marriage as if it has a confessional aspect associated with the sacrament, fine. Go ahead. Do it. But then please quit asking others opinions, and when they explain WHY, don’t try to diminish what they’ve told you.
I, personally, will not ever consider my husband for a confessor, confession partner or spiritual advisor. He is too close to the situation. It is the same reason I would not ask him to teach me Philosophy, or Math, or monitor my diet.
I, personally, think this is a dead horse, and hope the moderator comes to it soon.