It sounds like you are taking this one experience with your partner and generalizing it to all women. Obviously not all men cheat and not all women cheat either. e
i'm assuming that is what you meant by "fooling around"
my questions to you are the following:
1. Are you really wondering if women know the meaning of honesty and truth or do you just need to talk to someone to express your disappointment/sadness/anger etc?
2. If you need to talk to someone about this - would you like referrals to a therapist in your area (I would need to know the closest city to you)
3. We all choose people for various reasons. What made you choose to be with this woman? What kind of women are you attracting or attracted to emotionally? (sometimes we attract people that are unavailable because we fear being in a relationship ourselves - I am wondering if that is going on for you). Sometimes that is not the case, and our partner leads us to believe that they are faithful.