Is it normal for a 50 yr old male to have a strong sex drive, avg 3 times a day sometimes more?

It's a lot, for sure: If you define normal as average, or common - than it's not. But that's not to say it's abnormal. It might infringe on your opportunity to get other things done or to have a well rounded life. But, if you practice safe and non-violent sex, I doubt you'll do any physical harm to yourself or others. Also w/ high blood pressure, do lead a moderate life in terms of diet, rest, exercise, etc. Be well!