Do you think he is serious or he’s just playing me?

For the beginning, i’m F19 In february i started talking to a guy from tinder.We had a lot of things in common and we really got along very well.3 weeks ago we met for the first time and everything was perfect.We spent the whole day together, and it felt so good to be with him..i also gad my first first kiss that day with him. I got home and we talked as usual nothing seemed different and he invited me over to his place the next day.At his place we had watched a movie and we made out a little. In the evening when i got home i asked him if we are dating now and he said that he ruined all his relationships by rushing into them so he would like if we take the things slowly.Idk how after this we decided to become friends with benefits. The next day i went to his place again and it was the same as the other day.Everything was normal. But when i got home i texted him and he didn’t reply to my text untill the evening of the next day, telling me he was really busy and didn’t have time to respond. I continued talking but i feel like he got a little distant. A few days later he invited me over again and i agreed. I asked him again why he doesn’t wanna date me because we already do some relationship things.He told that he likes talking with me and he likes the way we are and wouldn’t want to ruin this, but if i really want we can try.I told him that i don’t want to force him into a relationship he doesn’t want but he insisted that he want the relationship but he’s afraid of ruining the thing we have now.In the end we decided to be together but he told me he wants to have an open relationship.He was really vague and i didn’t really understand what he meant when he said he wants it to be open.He said that he doesn’t mean we can date other people. I went to his place the other day and we did some stuff and after i told him i didn’t understand what he meant by open relationship and he only told me “you will see” A few days passed and everything is normal but i can’t stop myself from feeling that i’m gonna be hurt. I’m falling for him and all i can think about is that at any moment he will end things and it would break my heart. I really wish he would feel the same about me but then my mind keeps telling me i’m not good enough, he’s over my league and he will never fall for me.And the only reason he keeps talking to me is the s^x. Do you think i should try to repress my feelings now untill it’s too late? like i don’t know, in some way i feel like he wants something with me, but at the same time i feel like he’s still with me for the reason i said above. He wants something with me or he’s gonna play me until he gets bored and the he is gonna leave me? What do you think redditors?I really need some advice from you