Is it worrisome that I keep ending up in situationships and FWBs but never an actual relationship?

M27 here. I've been in a decent amount of situationships and have been in FWBs for way too long now, and I'm starting to wonder if something is genuinely off about the way I approach relationships.

Why is it that despite all of this, I've never actually been in a real relationship? Whenever I try to take things seriously or tell someone about my feelings, they either find it funny or just ghost me altogether. I mean, we go on dinners together, have late-night calls, and whatnot, but whenever I try to express my feelings, it just goes downhill from there.

It's great to have female friends with no attachments, and initially I liked it that way, but now I'm worried about why so many situationships and friendships are not culminating into an actual relationship.

The closest thing I would call a relationship was with this girl for 3-4 months, but when I told her that I'm not selfish enough to ask her to be exclusive, and to my surprise she just ghosted me all of a sudden — and the funny thing is, she was the one who told me that she just wants to go with the flow.

I just wanna have a female perspective where I’m going wrong ? Is it maybe because I'm autistic and struggle to read social cues the right way, or am I just too immature when it comes to handling real emotions and commitment?