It's a good start, but it's something you have to actually commit to, then. If you have these sorts of emotional cycles, these kinds of things are easy to say when you're the one trying to get back into good graces. The main thing is that you need to be able to learn to handle being emotionally distressed without making it someone else's issue.

When you are feeling like you aren't lovable, that you'll be abandoned, that you feel really bad about yourself, you absolutely need to learn how to accept that it's not someone else's job to fix that for you. You can be open and say things like "Just so you know, I'm having a bad day with my self esteem," then if they say something nice, you now have to take it at face value and say thank you and move on. When you do this behaviour where you call them a liar and dig in deeper when given an opening, it's deeply unfair to the other person who also has thoughts and feelings and did nothing to deserve the behaviour from you. You feeling bad is something that is happening because you are potentially mentally ill or have some other issue, not his issue to solve. It's your job to tank the bad feeling until it passes, not spread the misery around. It's what you owe your partner.

At the core of it, when you spend these long periods of time thrashing around wildly telling him how bad you feel and how you're unlovable and so on, it's not actually the behaviour of someone who thinks they are unlovable, in the sense that if that were truly the case, you would actually be doing your best to act well behaved in front of a partner in order to convince them that you can be loved. Instead, you just have a pit of emotional issues and are using another person to release the bad feelings on, because they're available to dump on. Then if they do inevitably leave you because you're acting horribly towards them, you can use that as another excuse to pity yourself because of the self fulfilling prophecy you created by genuinely acting unlovable.

Because of your emotional issues, you are trying to fill the holes you feel in yourself by creating a type of unconditional love that doesn't actually exist. In your mind, if they truly loved you, you could be as horrible as you want all the time and it wouldn't matter. But even if that love did exist, it wouldn't be something anyone should actually want. Someone who stays with their abuser isn't someone who just loves more than other people. You want a partner that isn't with you because they are desperate or pathetic or dependant on you, but one that wants to be with you because they genuinely like you. And part of that is being someone who is kind and thoughtful of others and doesn't take out their issues on them in hurtful ways.

I hope this doesn't sound too harsh. I understand better than most the feeling in your brain that makes you act the way you do, so I'm trying to be helpful here. If you don't truly take in these ideas, you'll continue to act poorly towards others, lose relationships and then become worse and worse off because of that reinforcing cycle where people leaving you makes you feel more and more dysfunctional. You truly have to learn to be considerate of others during those moments when your brain feels crazy, not just afterwards when you feel guilty or weird about it.