How do I change?

I am new to this so bear with me while I explain my story.

Ever since I was young I've had attachment issues where I hate the person for spending time with others and not caring enough about me. I've also had issues with compulsively lying in any situation I thought I would get in trouble and it could be for the dumbest things. Fast forward to 2 years ago when I was diagnosed with BPD, Depression, Anxiety, and PTSD. My therapist at the time helped me figure out that these were due to my childhood traumas (I won't dive into those here).

I have been in a relationship with my boyfriend for 8 years and he has been dealing with all my issues. My compulsive lying, major mood swings, seeming to lack empathy, struggling to care for myself and complete the easiest tasks. So naturally, by this point, he feels there is no end in sight and I will never change. I have gotten better about the mood swings and completing tasks along with caring for myself. But, my major issue is lying and hiding things. I work hard to try and change it, I will go for weeks without lying then something happens and I lie. Usually, it is for something stupid, like today I was watching a show while getting a snack together and I heard him coming down the stairs. I slammed the laptop closed and looked for a place to hide it so he wouldn't know. Obviously, he caught me, but instead of telling him what was going on, I lied even more. I dug myself in a huge hole and when he asked to see what was on the screen I had to fess up.

This then turned into an argument and he expressed the thought of leaving. I broke down because I love him but I am putting him through this pain of never being able to trust me. He has been dealing with this for so long that even with me trying to get better it is hard for him. I hate that I am putting him through this, I don't want to lose him. When things are going well we are so happy and we talk about the future. But the bad hits hard and it reminds both of us that I am broken and I am struggling to get better.

I have books to help, along with seeing a therapist. I had to get a new one recently and haven't been able to get into her until May. So, I have gone 2 months without therapy after seeing one weekly for almost 2 years. I don't know what to do, I want to change for both of us. I hate being this way and feeling like this all the time.

I just joined this site because I knew that it would be better if I had people to talk to with my diagnosis. See what they have found that works for them cause I don't know what to do anymore.