Support for a cheating wife?

I am married for 24 years and had 2 children, both girls, aged 23 and 18, the eldest one is married to the brother of my wife's lover.. My wife also had a son with his lover while i was working abroad.. Now our youngest daughter also had a son with her teenage boyfriend and is living together with my wife and her kid..I continued financial support for them up to the present time.. But now my expenses here in a middle eastern country is getting higher and my salary is still the same.. I feel obliged to help my youngest daughter and her child but i don't feel the same with my wife since she had a child with another man and acting as if nothing happened and not showing remorse.. I really need help on this matter because i am obviusly being used and i felt gravely dishonored for what they have done..i don't know how to face the people in our community ever since. I felt so betrayed i don't want to go home anymore. Thanks in advance for your advise.

You can only be obligated to give financial support to your children until they reach legal age.
1. Get proof of your wife's "activity". Find any means. Baka sa mga anak mo makakuha ka pa nga.
2. File for legal remedy.

You have some different alternatives:
1.. Get legal SEPARATION. (Or annulment. That's best to get, BUT that's more complicated, so it will probably take much more time and money.) Then you don't need to support her anymore legaly.

(2. But you risk to get legal problem if you go back to the Philippines.
Just skip supporting your wife. If she demand money you can:
a) say you will tell court about the adultery/concubinage if she demand support.
b) Just stay abroad and don't bother to say anything to your wife.

The above are rather simple. You have a biger problem though. The child is born inside your marriage, so you are counted as father, so you need court to decide you aren't father to avoid that child have legal right to support from you and will inherit you.