I have been in love with my sister for 20 years

She's 22 and I'm 31. I'm married and have 2 kids, but I've always loved my sister. She's amazing and beautiful, and she had to deal with a lot of hardships, losing her hearing, part of her sight, her health problems... the list goes on, but she's still an amazing person. I've been thinking about her a lot lately and feeling guilty about it.