All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
First of all, we ask Allaah to reward you for being kind to your wife and for seeking to respect her feelings and not embarrass her. This is indeed a good manner and a noble character, as the Prophet said: "The best among yourselves are the best to their wives." [At-Tirmithi]
If the matter is as you have mentioned in the question, then we advise you to be frank with her and talk to her about your need to satisfy your sexual desires and meet your affectionate feelings. It is an obligation on her to exchange these feelings with you and endeavour to make you enjoy her. It would be helpful if both of you beautified yourselves for one another. It is reported that Ibn 'Abbaas said: "Indeed, I like to beautify myself for my wife in the same manner I like her to beautify herself for me, as Allaah Says (what means): {And they (women) have rights (over their husbands as regards living expenses, etc.) similar (to those of their husbands) over them (as regards obedience and respect, etc.) to what is reasonable.}[Quran 2:228]"
So, if the objective is achieved, then all perfect praise be to Allaah. Otherwise [if the case remains the same], we consider that you should marry a second wife if you can be just between them; in fact you are obliged to marry a second wife if you fear temptation and fear committing adultery, even if marrying a second wife would lead you to divorce the first wife. Marrying a second wife does not mean that the husband does not love the first wife. 'Aa'ishah was the most beloved wife to the Prophet yet he married many other wives.
Allaah Knows best.