Men get worried about their penis size, if they think theirs is small they will feel inadequate and lose some confidence, if they feel theirs is bigger (but not abnormally big) they will gain confidence.
Bearing this in mind it is up to you what you feel you should tell your partner.
a player
You should be able to decide that for yourself. I say do what makes you happy.
Have as many as you like who cares what people think ...
Being promiscuous (having a lot of sexual partners) does not create HIV - you have to be infected by one of your partners (or by some other means on transmission). The fact that you are promiscuous (have a lot of sexual partners) does not significantly increase your risk of contracting HIV. The risk would arise if you were not having safer sex with them.
If you truly love him, you'll fully trust him... That does not mean if you love someone you should have fully trust on him because if you show him that you trust him he may betray you...
me
Risk of vaginal infections is increasing with number of sexual partners especially if partners had other partners before you. You can check below (in recommended link) all vaginal infections and discover how you could get it.
She Was Married Twice. 1. Sean Penn 2. Guy Ritchie.
The more sexual partners you have, the higher the risk of catching papaloma virus which causes cervical cancer
Well, do something you have never done before or take your wife or husband on a romantic getaway
They are called bi-sexual, instead of heterosexual.
It's a purely subjective, esthetic call, and it depends on what your preferences are and what your sexual partners' preferences are (if you care about those).