help me

A friend of mine slept with her ex and he is a frat President for only one night & 1 time... long story short she got chlamydia from him. He got tested & told her to get tested.

Later she meets what seems to be the perfect guy damn near. He does come with a past but everyone does. He is amazing and she is the happiest she's ever been.

They slept together and then started building a relationship. Now she isn't sure how to tell him about the situation with the ex & her results came in positive. Yet, she is still sleeping with new guy, just protected.

My question is what steps should she take to move forward? How should she tell him? And do yall feel like their possible relationship is now never going to start?