<human>: [English is not my first language]

Hi /r/relationships,

I met Marc about 8 years ago, we were in the same friend group, but weren't friends. Last year we began to talk more and started a relationship. The relationship lasted only 4 month, because we didn't enough time for each other. I also discovered a conversation between him and his fling before me where he told her that he wouldn't have started something with me, if she wouldn't have broken up with him. (I felt like the 2nd choice) He also told her, that he don't know if the realationship with me is the right thing.

I broke up with him, but I didn't tell him about the coversation I read. It was all very amicable and we stayed friends afterwards. But because we didn't have much time to spend with each other we drifted apart.

Fast forward end of december. We see each other at a party and eventually made out toghether.  One week later, the same thing: party - making out.

We started meeting up again. We also started sleeping together. We decide that we do not wan't a relationship, but fwb suits us best. I was very happy with this arrangement.
The fwb started to shift more and more towards a relationship. We would hang out and doing couply stuff. It was great. I noticed he started to have feelings. He treats me perfectly. He is so considerate, listens to me, helps me with everything. He is just like the boyfriend I ever wanted.

We talked with each other, if we want to start a relationship. He wants to, he is happy! But I am not sure. I have some serious issues, like social anxiety, insecurity and jealousy. I know these problems will interfere with my relationship. I don't want to burden him with my problems. 

I don't know what to do. I really want this relationship, but I don't know how to have a healthy relationship with all my probmlems.

What should I do? Every advice is welcome!

Could you distill the essence of the text into 1-3 sentences?
<bot>: FWB an I are getting very serious. We both want a relationship, but I don't know if it is the right decision because of my insecurity and jealousy.