I feel totally selfish asking this question, but my boyfriend just wont talk about things. He was born with a heart defect and had needed a new heart valve aged 15. He had endocarditis in July 10,and has been told he needs to have the valve replaced as the endocarditis has savaged it, and is regurgitating blood . He is more tired but tries not to let it effect his life; he does everything now that he has always done he just tires alot more quickly. His sex drive has totally diminished.Is this normal? May seem a stupid question but when i ask him if he thinks its due to his health he wont talk about it. I ve tried googling but lack of sex drive is not listed as a common side effect