Question on US Citizenship

[csanti]

I am a naturalized US citizen through marriage and been married for 16yrs. I am separated for 2yrs now and going through divorce and was wondering if I will lose my US citizenship after divorce. I originally came here as a tourist visa and overstayed. If I don't have to worry about my citizenship, I recently got in touch with my high school sweetheart in the Philippines and would like to petition him and his 2kids (under 18) through K-1 visa and get married here in the US. Would I have a problem in petitioning him after my divorce because I overstayed as a tourist originally? Also, reading through the instructions on the I-129F, is the fee of $455 a one time payment for the application process or is it per person (my fiance and his 2 kids).
Thank you so much for anyone who can answer my question.

[PraetorianXI]

you can not lose the citizenship. And since you have been married for so long, i doubt it will be a problem to sponsor someone else for a K-1 visa. Also the fee is for 1 application, not per person.