Will A Band In The Centre Of Penis Effect Me Sexually As I Have Trouble Maintaining An Errection?

hi I have been to my doctor several times regarding what I believe is a problem
I'm not sure if this is the right place to ask this question but here goes anyway.

My penis has a band in the centre it contracts to a very thin band apprx 1/2 incch long.
It happens when it gets cold but not only then and it prevents me from finishing my urination.
my question here is because it stops some of the flow of urine will it also effect me sexually as I am having trouble maintaining an errection.

I hope you can help or at least point me in the right area

Thanks