Hi "Bee" ~ Bless your heart, I can almost feel the depression in your words.
First I think you should see your medical doctor to make sure everything is ok there. Sometimes a simple blood test can answer all sorts of questions and tell you what is wrong. It's worth a try.
If all is well there, then a good therapist is in order. Something is bothering you and it may be something you aren't even aware of - or you may know what it is, but don't know how to handle it. There is NOTHING wrong with seeing a therapist ~ I've been in therapy on and off most of my adult life. I'm a better person for it.
And please don't worry about your husband. We can't change other people. If he sneaks and looks at porn, there's nothing you can do about it. Nagging, pleading, threatening won't work. It's like an addiction - he has to WANT to stop. You can't MAKE him stop. God bless you Bee, and take care of YOU. Hugs, Lee