Oh, I am so sorry to hear this. I do not think you are a horrible person. And you need to do what's best for all involved, especially the children. You may not want to, but leaving him, though it may hurt deeply, would be in your best interest as well as your family.
There is just so much one can do, and so much you shouldn't have to.
Sounds like you've done everything, and now you are hitting a cement wall, may be time to part, before you are consumed any further.
I noticed you mentioned anti-depressant, but if he is Bipolar, it's more important that he takes a mood stabilizer, anti-depressants aren't going to do much for him if he is bipolar, but it's not uncommon that they are added in while taking a mood stabilizer.
Does he see a pdoc or just getting the AD's from a family doctor? He really needs a psychiatrist for proper evaluation and med treatment plan.
I'm sorry to hear what you are dealing with, at the bipolar forum you'll read a lot of posts very similar to yours, feel free to check them out.
I wish you lots of luck with this, it is very draining, I'm sure. Though it may be drastic, keep in mind if he doesn't care to follow a treatment plan, and chooses to remain going on like this, maybe a seperation or even divorce is the next step. It's unfair to you, and yes, even him, to stay together in a toxic relationship. You need to think of your own preservation, life is too short.
Is it possible his depression is due to wanting out of the marriage and doesn't know how to deal with that? Seems way out there, but cases like that happen too, a person may not have a problem, instead both are having personality clashes, which maybe at one time the couple got along fine, but time and age can change things.
I pray you'll get some peace, and he follows a med plan and even therapy, will he couples therapy a try?
Sometimes hearing from another person stuff about his behaviour may make him realize or think about things.
Just some thoughts here.
Please take care,
DE