I agree with Sand 10,000% - I hate to break it to you - but your H IS for sure having an affair and he IS putting you at STD risk and that is a present that will not go away.
I pray that you will get the strength to confront him TODAY -without delay - stop sleeping with him and get a medical evaluation for both him and you.
Time to stop the denial - it will only get worse. This is an extremely difficult thing for you to confront, but putting it under a rug and pretending this is not happening is going to bring you a world of hurt.
Time to be brave and strong
FL
M-58 W-56 Married 33 years BOMB -Sept/10 Separated 8 months
BITS (of Fruit) Firstlove
"Go Confidently in the direction of YOUR dreams - Live the life you've imagined" - Thoreau