Advice needed

I’m 5 1/2 months pregnant with my boyfriend of two going on three years. I just discovered that last week he was sending flirty text messages to girls on Snapchat and actually messaged an escort. He said it was nothing more than him sending messages and that no one replied to him but now I can’t stop comparing myself to them and just thinking how I’ll never be good enough even though I do so much for him. What should I do?