I need serious help before I make a huge mistake ?

Okay so I’ve been with my boyfriend for 3 years now, gonna be 4 in November, and we had been doing long distance because I’m in another continent for uni. Then a year into our relationship I took a hiatus so for 2 years I was home. Now I am back in school and I’ve been very busy and he isn’t taking it well, he’s always complaining about me not giving him enough time on the phone or he complains that other people get my time rather than him, he’s coming off very insecure and we argue all the time which just drains me because we I could be studying. Another issue is I’ve met this guy who is the complete opposite! He’s confident h helps me with school and he’s not so naggy! I mean when my best friend posts me on instagram he has to do the same the same day and if I don’t repost him like I’ve done her he gets upset! He always says he hates that other people get my time and I’m just so turned off by him right now! And I was so ready to marry him but I’m terrified at the thought of him proposing I would say no! I’ve thought other guys are attractive before but this new guy I hate to say I have an emotional connection to him :( I don’t know if I’m just tired of my current relationship and I’m using this guy as an excuse to jump ship? He was my first and I never thought I would wish I had a little more fun but I do, I’m now wishing I didn’t jump into it, feel like I’m going and suffocated and can’t do the distance anymore!! Please help!!!