Confused about my feelings

I’m currently “dating” somebody. I like him and he treats me well, we’re not together officially. However, I’m not over my ex, I still love him and he’s told me he wants to try and sort things again. We were together for 5 years and made a mutual agreement to split up as we felt we were still young and had a lot of living to do. We’ve both tried dating other people and it hasn’t worked out.

I’d feel bad if I had to end things with the person I’m dating because he’s genuinely lovely and he likes me a lot. But I always get told to put my happiness first yet I can’t bring myself to hurt the person I’m speaking to.