He cheated on her with me and I didnt know

So a fwb I met on tinder , we got to know each other and had sex twice but I did some research on twitter to find out he has a gf in another state where he is from because he is stationed here for military for the next three years, so I feel so fucking terrible because I just got out of a relationship where I was cheated on , and now it turns out I was the other girl so idk what to do. Like we would talk everyday from morning to night and he would tell me goodnight every night and was just lovey with me and I just feel used and like it was my fault because I should’ve checked first...