Ex Bf/New Bf

I had been in a on and off relationship with my ex. I had been with him from July 2017 up to October 2018. It didn’t work out because he’s in the military and he was always so far away. We got to a point where we could no longer fix the rough patches and we went our separate ways. I started a new relationship in February this year and it’s going good but I’m still sad over my ex. I don’t know why but it’s still difficult to get over it. We broke up and talked in a fair manner, we haven’t been in touch since the break up and I so badly want to reach out to him. I leave for bootcamp June 10 (it’s March 27 today) and the new guy I’m with wants me to stay. He knows when I leave, our relationship will have to end. I couldn’t put him through the same thing I went through with my ex. He said he’d take care of me if I chose to stay, we’d get our own place and he’d pay for it all, I wouldn’t have to worry about housing. He’s financially stable and will get his grandfathers company and his fathers company once they retire in a few years. I miss my ex but at the same time I want to further my future with my boyfriend. He’s so kind and treats me so well but my heart still aches. What can I do for myself to chose the right path?