Is it obligatory to inform the second wife about delayed urine drops, erectile dysfunction, and the presence of white lines on the thighs and buttocks, in addition to the presence of artificial dental prosthetics, for the marriage to be valid?

The defects that must be disclosed to the suitor are those that prevent sexual intercourse or contagious and repulsive diseases. What you mentioned about yourself does not fall under these defects, therefore, you are not obligated to inform the fiancée about it.

We alert that marrying a second wife is conditioned upon the ability to provide for both wives and to be just between them.

It is advisable to search for the reason behind the wife's ill-treatment and to rectify it if it stems from you, or to reform her if it stems from her, while considering the nature of women as described by the Prophet, peace and blessings be upon him: "And treat women kindly, for woman was created from a rib, and the most crooked part of the rib is its upper part. If you try to straighten it, you will break it, and if you leave it, it will remain crooked. So, treat women kindly."