How do you know when you want to be in a relationship with someone?

Confusing title and question I’m sure so let me offer some context.

I’m in my late twenties and have only ever been in one real relationship which only lasted a few months. However when I met that woman we instantly hit it off and for reasons I still don’t understand I just knew I wanted to date her, even possibly for the long term as I once thought I loved her. We broke up because she treated me horribly and only cared about herself.

Since then I’ve gone out with a semi decent amount of women and have yet to actually consider dating any of them. There was nothing wrong, all very attractive, kind, had similar interests but for one reason or another I just didn’t feel that special something towards them.

What’s so confusing for me is if I was even really into my first girlfriend or if it was just a placebo of finally experiencing a relationship for the first time or just desperation.

Basically I’m just looking for advice from others on how they knew the person they went out with was someone they could see themselves dating. I have absolutely no idea what to look for or what I’m suppose to feel.

Yes, I am genuinely seeking my special person and long term relationship but perhaps I’m just scared to committing to the wrong person again and regretting it. I just feel guilty because I’ve had a new FWB for a few months now and recently she essentially asked me why I didn’t want to date her or it seemed like I wasn’t interested in anything serious and that’s not the case at all. It was really hard to explain without hurting her feelings that I really liked her but the emotional feelings just weren’t there but I couldn’t explain why. Maybe it takes longer to develop with some than others?

Is something wrong with me?