Dating someone whose just came out of a 7 year relationship?

Iv met a guy. A soldier. Sparks grew instantly but his been with someone for 7 years, he is only 22 and im 18 they broke up last christmas and he says they don't keep in touch but he had a letter from her in his drawer that i saw. It said 'dear future husband' aswel. But well me and him made love on the second date and he keeps telling me now that he is giving me his love bladiblah it was love at first sight. Real sweet guy but he only broke up with his ex because of distance, him being a soldier and all...he also told me he still cares for her and doesnt want to lie to me but he is done with her. Should i trust him?