I'm not ctb to help others
I'm doing it for selfish reasons despite knowing it will hurt others
I feel so guilty (but apparently not guilty enough not to do it)
I hate myself for not loving my family enough
They're going to think I didn't care about them
You can always write a note saying otherwise. Sadly, you won' be able to control how they respond to that. Guilt is a complex thing and as someone who is not you, I won't know exact,y what or why you feel guilt, but I'll still give my two cents. Take it with a grain of salt tho.
Your life is yours to deal with and do what you wish. The way I see it is that the burden of grief is for the person experiencing it to deal with, not the dead person. Hurting someone does not make you a bad person. Obviously there are consequences for every action especially CBT. I'll be honest suicide can really destroy people even when you don't intend it, but some people can also leave unscathed. I know I'm the latter but then again I've heard this line of thinking is uncommon. Point is, you have no control or responsibility over their hurt, only your action.
If I were you, I'd ask myself why I felt guilty first. To process your own guilt you also have to question why you want to CBT in the first place in my opinion. Sometimes you have to put yourself first and maybe you'll put others first. Either choice does not make you a bad person. It doesn't necessarily mean you'll be betraying yourself or them whichever you choose. As always, quick reminder to only do CBT if you're without a shadow of a doubt.
With things like guilt, there's no correct or wrong response, I hope to offer you at the very least, my perspective and how I personally view it. Do with this what you will. Good luck with whichever you choose.