I really do empathise, OP, I have been there too. I was very shy in my teenage years/twenties, so didn't have any dates and didn't have much experience of getting to know the opposite sex. I happened to be asked out by someone who seemed ok and who ticked a good few boxes, so I thought I'd give it a go.
I thought he seemed nice, told me he loved me, but I didn't know how I felt - I asked for advice about what it feels like, and no-one could tell me anything other than "you'll know he's the right one." Also, following the other advice that "in love" was some kind of temporary insanity, which was essentially meaningless when compared to the deeper love and companionship which develops over the years. My mother freely admitted that she had not married for love, she thought my dad was a good man and they could get along, and they were married for 19 years before he died.
Anyway, with this pieced together information, and not having my door battered down by any other suitors, I married him. Funny thing is, even then, I knew I was never "in love" with him (even though I didn't know how that felt) I had worked out from others that, apparently, this did not matter, and the fact that I loved him and thought I could get on with him as more important.
Fast forward a few years - unhappy relationship, H not nice and kind, actually emotionally abusive, I blamed myself because I knew I was never in love with him.
Anyway, I met someone at work. Immediately felt like I'd known him forever, I said "you're like my brother or something." Brain worked in the same way as mine. Thought he looked nice, but wasn't instantly attracted, but then, I wasn't 'looking'. Got talking, started going out for lunch, had fun in a 'friend' way, we had lots in common, but never even considered him as a potential partner (was still married). Gradually realised that when I went home, it was going to a house, but when with friend, I felt 'at home'. Only then did I start getting that gut feeling, literally a tightness in my stomach, it just felt like a complete certainty. My eyes were then opened, and I realised I was deeply attracted to him as well. I realised that what I was feeling was that I was in love.
Anyway, it was complicated and heart-wrenching, but I knew all along I should be with him. We didn't actually get together until 3 years later, but we have been together 10 years. :)
In summary, the difference between simple infatuation and being in love, IMHO, is the feeling of complete certainty that you have arrived 'at home'.
HTH a little, OP?