This is a cliche, but, it appears she's very unhappy in the marriage, is trying to find herself and has decided to try something new and different. It isn't uncommon for some women to find out they just don't seem to connect with men and end up with another woman. It's possible she comes to realize she isn't a lesbian, but it's a risk. If she hasn't contacted you and given you any indication she is coming back then it's doubtful and you should move on. Of course it would only be right that your teenage sons get to see her only if they want too. Remember, your sons are caught in the middle so no matter how hurt or upset you are at her choice of a new mate try to remain calm and not let your feelings confuse your teenage sons. She is still their mother. If you don't want your sons seeing her with her female partner then you can arrange something else so your wife is alone with her sons or you are present.