We Live In In An Area Where The Temperature Rarely Drops Below 26C

We live in in an area where the temperature rarely drops below 26c, nudity is ok in the family i asked my wife do we carry on in front of my step daughter now she is maturing body wise,
I asked about me getting an involuntary erection do i cover it up, my wife said no its a natural thing if she is going to see a hard dick it should be yours, i admit she does disturbed me, she isn't fussy how she sits with her legs open and she bends over in front of me showing everything i think she is doing it on purpose and its having an affect on me, i have an erection when ever she is around