Guy advice

Hey so I’m 19 and I’ve known my boy best friend for 6 years went to the same middle school and high school and never left each other’s side, until the rumors started. Everyone kept saying we were dating but we never did. Just this past year he joined the marines and our friendship has always been on the rocks until he was getting stationed in Hawaii. When he came back for pre stationing we both confessed feelings for each other and then everything went down hill because I got afraid. After that he left and did field training in Arizona and California. By this time another marine who is in japan rn and goes back to Hawaii in December, we started talking and everything is going great, but now my best friend is back before shipping off to Japan also and I can tell that we both still have feelings for each other and it’s weird that when he’s gone I’m okay and live but when he’s here there’s just something that tells me it’s okay to try, but I don’t wanna ruin our friendship and the other marine and I have grown a bond and he comes back at the end of December to be with me. And my bestfriend is the jealous type who makes it a point he has feelings when he’s around and I bring other guys around. So at this point I just don’t know why to do anymore. HELP!