My husbands best friend

My husband has a best friend who starting coming around 2 years ago with his wife cheated on him. Well over the past two years, he has become my best friend we have been through a lot of the same things, we like alot of the same things, we even have similar personalities.

Growing up I was a lone. My parents weren't the best parents and I didn't have really anyone to talk to. So it's a change to have someone who understands me.

I love my husband so much but when his friend comes down its like a get a crush on him for the 2-3 days he is here then when he is gone so is the crush🙃🙃 Its so weird. Makes me feel like I'm a bad wife and a terrible person. Is it normal? Any advice?