None of them were actually helpful, though.
I hear you. It’s hard to find the right one. It’s a matter of relationships and learning to trust each other… sometimes it doesn’t match and that’s okay. I’m glad you kept looking for a therapist with whom you’d feel comfortable. And I’m really glad to hear about your current therapist.
Though, it’s okay to take your time to trust him. For what it’s worth, I’ve been where you are now. It’s hard for me to trust others /w myself - even professionals. So if it’s about discussing painful or intimate things? No way. But there’s a reason behind this: it’s just how I learned to manage pain and sadness for as long as I can remember. I didn’t have a safe environment around me to actually share that kind of thing, for too many years. I was used to bottle up, cry in silence or when no one sees it. Just like you who’s used to put others first. So when I had to be in front of a therapist and respond to this question: “why are you on therapy?”. Wow. I’ve been repeatedly silent and very anxious, like my brain couldn’t function anymore.
You know that already, but the main purpose of a therapy is actually this. To provide you a safe and healthy environment where you can get things off your chest without any judgment and despite your fears. You can see it as a place where you can try, eventually fail or succeed, then try again. It’s okay not to know how to really talk to them yet. Take your time.
Maybe something that could help is to share about this struggle, if you didn’t yet. To say, directly: “I don’t know how to express myself with you/I have no clue/I’m lost”, so he can try to help you for that. He can’t guess what’s preventing you to discuss unless you let him know. You can give him some clues for a better mutual understanding, so he can try to progress with you. If you are more comfortable with writing, maybe it can be something you could use as well. Writing him a note, a letter, or even a drawing. Something that could help you to communicate in a more comfortable way.
Every time I get asked, why I am in therapy by my therapists, I don’t have an answer. I just don’t know.
The reason why they ask this is to be able to progress in an effective way with you, also to have kind of small goals. It’s also a way to let you guide them because you have all the resources you need in yourself already, and their role is to be a facilitator in your life. But it’s okay if you don’t know how to respond at first. You don’t need to have all the answers. I think a lot of people who decide to go on therapy are lost when they start to go there. Just because we’re more likely to make this decision of reaching out when we’re really down and overwhelmed. In other words, when we need some clarity. So we’re actually seeking answers but don’t really know how and what. Therapists are used to that. It’s okay.
It’s also an interesting question to keep in mind for you everytime you see him. Maybe you don’t know why you’re on therapy, but you can always decide: okay, this session, I want us to work on this thing precisely. It’s a first step. 
Was a great speech to let go of all the shame and guilt to feel how I felt.