in love but not together

ive known this guy and been im love with him since the day i meet him, it was just kinda a "damn hes wow". but he had a gf and i respect that shit. anyway hed kinda flirt with me and id flirt back, hid gf is a cheater and theyve been on and off this whole time. we tell eachother everythibbg and he really doesnt love her anymore but thats just what his comfortable with because theyve been together so long . shes jelous of me for some reason because i try to poliet to her and i dont like drama so i really try to keep to myself but she acts like we are the greatest friends and talks shit about me. hes going to boot camp on the 5th and then to germany. i made him promise to write as much as he can but hes not even gone to boot camp yet and i have this like constant anxiety in my stomach im so scared somethings goin to happen to him and i feel bad cause i cant talk to anyone but him about it or i a hoe tryna wreak a relationship thats already falling apart its stressful and i just need some advice