We were marriage for 20 years. I noticed my wife is becoming secretive and she changed her sexual mood in the last six months. Until I discovered that she is having an affair to a lesbian. My question is Can I file for a legal separation?

Sure you can file for separation. Get yourself an attorney.

An affair is an affair regardless of whether it's a man or woman, so yes she's cheating on you!

If you don't want to cope with this behavior, then you should contact an attorney.

The real question is do you want to file for a separation? I mean wouldn't you want to noe some answers before just jumping into separation? You guys have been married for 20 years for pete's sake!