It became a religious and cultural custom as a right of passage in manhood to slice and dice the penis. Circumcision is the least invasive of that. Sometimes because of infections, there had to be an incision to let the penis emerge. In some cultures, circumcision is much more invasive, for example, slitting the urethra all the way to the head of the penis. There is usually no medical reason for circumcision.
Circumcision has no impact on sexual pleasure.
Cross-dressing is an interesting and curious, yet accepted, phenomenon. If your partner doesn't care and you don't care, then it isn't a problem. There are some clubs where men completely take over the role of women and sometimes their wives go with them and help pick out their clothes. Emotional readiness for sex is really important, and I am glad you asked. The only way to know is to talk to them and share with them.