Unstable relationship

Me and my boyfriend have been together for 3 years. He's in the army and last year we got engaged, but after our engagement I found out he created a tinder account and started flirting with this girl that lived far away from him. he said he did it because he was bored and he wasn't even planing on meeting her that's why he looked somewhere far away from him. And he deleted his account immediately after I confronted him. Anyways, I still called off our engagement. since then I've felt like I shouldn't be with him, but when I'm with him I just forget about that and it's like nothing ever happened. But deep down I have a feeling I'll never be able to feel genuinely happy with him again. Do y'all think I should break up with him or keep going.