Asking for a friend.. How will you tell your 7/o son that you are now dating another guy? He's aware that his mom and dad are no longer in good terms and are not married.

I agree with Beatriz. It's best to hold off the meeting part until everything between the dad and your friend has subsided. After that, I suggest to take it slow for the child. Why not introduce the new guy as a friend at first? Then maybe that's where your friend can start working on. Personally, I think she should just keep it that way until the kid is big enough to understand things even better, so as there wouldn't be any confusion. At 7 y/o, it's hard to grasp things like intimate relationships. Again, that's just my two cents :)

I think it's best to introduce the idea to the child little by little. For sure he is aware of the tension happening, so it would be best to talk to him and explain the situation. Based on my tita's experience with my cousin, she didn't introduce him to another guy right away because her son needs some getting used to. It took them around a year before my cousin met my tita's boyfriend