heartbroken

Ta
Months ago I caught him romantically texting this woman and confronted him about it. At the same he thought we weren't that serious I guess and he swore that going forward I was his 1 and only. He changed his phone password and now many months later I decided to check his phone again since I figured out his new code and I find this. "Missing you" I'm so heartbroken. I am finally ready to tell him I love him (since he hasn't said it yet) and now I don't want to.
Bit of context, this woman he told me they dated before and they are just friends now. But he had texted her romantic things & sexted her months ago.