How to tell someone you miss them without suffocating them?

r/

Hi, this is my first post so bear with me. I’ve been talking to this guy for almost 2 months now. I am 18F and he is 19M. He has been very on and off with me since about 3 weeks into us “dating” (if that’s what its classified as). Everytime he’s left, he’s also been the one to come back. Him leaving the first 2-3 times have been because of his own insecurities and doubts about us working out. To clarify, he strongly believed that he wasn’t deserving of a relationship, especially with someone who truly cared for him. We had a long fight about it, and he revealed that he thought he’d bring the worst in me out, that he didn’t deserve me. We got past it, especially after I was fully transparent about how i felt. He came back, we talked, he left once more 2 weeks later for the same reason then came back again. He bought me a stuffed animal that i’d wanted and went out of his way to get it, put it in my mailbox for me with a sweet note that he missed me. Everything was good until he left one more time, about 2 weeks ago. (Mid August) This time when he came back, he called me and finally spilled everything he felt about me (which he’s never done). He said he knows he pushes people away and that he was ready to accept my care because i was who he wanted. We got back together. A week later (August 23rd), he left again. He told me alot of shit has been going on in his life, even prior to him coming back, that he wasn’t a good person and that he would keep in contact with me, but we weren’t going to be on “relationship” terms. He then proceeded to barely talk to me and we had a huge fight over the reason he left. He stuck to the story. Bad personal life, needs to get his shit together. I want to believe the fact that it’s genuinely not me and something must be going on in his life, but I can’t understand or comprehend why it had to include leaving me again. I trust him, but apart of me feels that it’s an excuse to talk to other people and slowly branch away from me, as it’s happened to me in the past. So im asking if this is something common (or at least what someone else has gone through), and im asking how did that end? What did you do to get through it? Did you guys talk? Do I fully leave him be?
Thank you.

TLDR; Guy im talking to leaves constantly, we’re finally back on great terms and perfect communication and he leaves AGAIN for “personal things he’s going through”. He has a past for having a hard personal life. Should I be worried? Is he just using it as an excuse? Do I reach out, or leave him be?