Gosh. Sex. First of all the male and female perspectives are different. But generally I would say there are four dimensions.
1 what changes would have happened anyway
2 psychological impact of pd
4 pd physical change
1 - as we get older some of us get less randy, in particular the post-menapausal ladies (feel free to put me right on this one). Partners may not be quite as stimulating as they once were.
2 being 'diseased' can make us feel unattractive,
3 most drugs enhance libido - libido being keenness rather than performance. Especially Dopamine Agonists. Anti-depressants tend to depress libido.
4 PD can cause performance problems but I personally don't think it effects keenness.
5 Alcohol in large quantities is not good for sex.
Personally, I find the best thing for enhancing libido is to .....nah, I'll keep that private for now.