Afraid of hope

I'm new here, but been through all this crap too many times before. A few years I was a member of a different forum but they seem to be gone now so in my need for support I stumbled across this one. The back story is too long, but if those details are needed I will spend the time to type them out.
I have been with my BF for almost 15 years. He's lied for most of that time. Each discovery has been more painful than the last. The first few times I stupidly believed he would stop. It never happened and our sex life has suffered. About 3 years ago I found out about PA and we both joined the other forum. I thought he was serious. But, I don't know. I'll skip to this last blow out. For the last year I've known something was up and asked him countless times. He always gave me the same answers, saying he understood my fear and distrust. This last year has been the worst for me, I've been distancing myself. Screaming in my head 'I don't believe you!!'. I have anger issues, my temper is very short but I know this and am still working on controlling it. Oddly when it comes to my BF my anger is controlled. But I think it is replaced by depression, which I also have a problem with. My whole life I've struggled with depression, anxiety and anger. But when things are going good with us those things are not a problem and go away or lessen. We both have health issues, autoimmune diseases (different ones, though both diagnosed young) We get each other and when this PA doesn't get in the way work great together. Anyway, it came to light he was still doing it. I mean, I knew but didn't have proof. He's back and forth with it is PA/it isn't PA. His feeling is that because he doesn't do it 'all the time' and doesn't think of it all the time it isn't PA. I don't truly know if he thinks it is or isn't at this point. We have talked, and he does answer but is embarrassed and I don't feel is fully honest. I don't know if he is completely honest with himself. He is reading your brain on porn, has been on the site and has been looking around this and other forums. But I'm afraid to hope. Hope leads to pain. We've talked about a therapist/s. I don't know if it would help me, and I have very bad social anxiety. I don't know if I could talk to one about this. I understand this PA isn't my fault but emotionally I feel it is my fault. At least partly. I also have no idea where to find one that could help with this problem, a CSAT I think it is. But I also fear I'll be told to get over it, there is nothing wrong with PMO. Everyone does it. So round and round my thoughts go.
Sorry, my thoughts are swirling and I'm probably rambling now. I am willing to give this another shot. We've been together for so long and I do love him, though I hate him too. That hurts. I told him if I find out he is lying I'm gone. I can't do it again. But if he is truly trying and has a slip up and comes to me we will work through it.

 

Thank you for the support. I want to at least start looking for a therapist I think. At least have some names. My social anxiety is just so bad that I sometimes loose the ability to speak in social situations. It is actually scary, I couldn't remember words. I just so want to fix this ourselves but it hasn't worked so far and I have the feeling that help would, well help.

 

Having a hard time today, I honestly wish I was feeling numb instead.

 

Thank you both. We have been talking, more this time than before. Though I hold some things back because I don't know what is important to say and what isn't. Also I don't want to hurt him more. Some of my problems, telling him about won't make them go away, we can not go back and change the past. Some of the things I want to know about I don't think I really want to know. The knowing won't make me feel better and again, will not change what has happened. I've been writing all my questions/thoughts down and then thinking over them, will knowing the answer help us to heal? He has always had my help, I offer it gladly. We both have health problems and take care of each other. He's been in the hospital maybe a half dozen times since we've been together. We have also gone through hard drug use together. We quit with each others help and support. He does keep going back and forth on addiction/not addiction. But he is reading books and websites of his own initiative after I showed him a couple. He says he wants this shit gone from our lives, he says all the right things. But I'm afraid to believe him, and honestly I don't know if there will be real trust. Logically I think a therapist is a good idea, emotionally it scares the fuck out of me. He says he is open to anything that will help us. I think I really scared him and maybe hurt him this time. When I found out he's been lying again I told him I wish I never met him. I saw the pain at that. And I'm so sorry, but it's a though I'd had a lot over this last year. Would I do this all over if I knew how it would turn out? Would I give up everything we've had, the dogs(no kids, we don't want them but the dogs are our kids. We've lost the two oldest in the last six months. And now our 18y/o cat has cancer. I've had that cat since I was a teen. We've been talking about adding a second dog, but I said I wanted us to be better first. I didn't feel our relationship was in a great spot. I needed some trust. He said that was fair and then continued to lie to me.)
Anyway, I don't know if I would do it all again. Even all the good and love. That thought hurts me, tears me to my core.