@Brave through Don't worry about the length it's totally fine, situations are complex and can take a lot of explaining. I totally get where you're coming from, it sounds like you have a big fear of letting go, losing someone, having someone lose feelings for you, and change, all things my OCD can make me go crazy about too so I can totally relate. My last relationship, I was so worried about all the what ifs and if my gf was going to lose feelings for me, and anything else my ocd was trying to latch onto to hurt me with, that I lost sight of the relationship itself and wasn't as in it as I should have been and I let the thoughts cloud my judgement. For struggling with the uncertainty, that is definitely something I struggle with as well. Wondering how that person feels and if they are lying are just trying to be nice, it can be torture. As counterproductive as it sounds, what worked best for me is accepting the uncertainty. Like me, you want the guarantee he's not going to leave or lose feelings, but as much as it sucks, we can never guarantee someone else's actions and feelings, and it just causes hurt when you try to. It's like trying to overpower something you have no control over, which is more emotionally taxing and draining than anything. Try to accept that you can't guarantee things, but you can do what you can to enjoy your time right now and take steps to strengthen yourself and get into a good headspace where you can accept those uncertainties and not let them weigh on you so heavily. I used to stress daily my gf would find someone better while we weren't talking and she was at work, or she would have enough time away from to think she was fine without me, but that's not the case. We can't control those things, and spending energy worrying about them will just lead to more pain and struggle.
For advice on your situationship, I'd say just be open with the person you're talking too, about how feel and what you want from your relationship together, weather it be continuing what you have or evolving to more. Just understand that whatever happens, try not to let your OCD get a grasp and cause you to spiral, as that's happened to me. When the thing I was scared of happening happened, I took a breath knowing that I was facing what OCD made me so afraid and sick of, and I was okay