What is love for a partner supposed to feel like?

I thought the love I felt in high school was how love was supposed to be, even if it was puppy love. All I wanted to do was see that person, like a puppy I suppose and I fell head over heels for that person. I felt butterflies in my stomach whenever I got a message or email from them.

I tried to have a relationship with another person after high school. I feel like maybe I loved him sometimes? But I didn't fall head over heels for him. It was a small crush that I went with. It felt like a straight line throughout our relationship. I didn't really get butterflies in my stomach either. Sometimes I felt emotionless towards him.

I'm trying with another guy, but I'm not feeling much chemistry. I feel emotionless again.

It's a long story, but I've been thinking about the guy I had a relationship with after high school.

I genuinely don't know what to feel or think anymore. Let me know your experiences. How is love with your partner supposed to feel like? Thanks in advance :)