Annulment to be Filed by the Cheating Husband

I'm married to my husband now for 3 years and we have a 2 year old son. Our marriage was on the rocks when I learned about my husband's infidelity, and it even makes the depression worst when I found out that he is having an affair when I was still pregnant with our son.
Before we got married we are in a 11 years bf-gf relationship.
My husband and the mistress (His office mate) is denying the affair at first. But later on I was able to prove by hiring investigator and some eye witness when they check-in in a hotel and in the malls, as well as sweet text messages and love letters thru email. When I have all the evidences, there's no denying on their part. Eventually the mistress apologized and admitted her mistakes.

Now, my husband is furious with me for revealing everything and putting him in shame to their office. Because I reported their office affair to their bosses and forwarded all of my evidences.

He threaten me that he will file an annulment to end our marriage because he doesn't want me anymore.
And now he left our home. Leaving me and our son alone.

Now, my question is; Is it possible for him to file an annulment when he is the one who cheats and broke our vows? Will it make it more successful for him to file now that he already left us and not living with us for almost a year?

Truth is I don't want to agree to the annulment in case he really do file for it. Because I still want to fight for our marriage and our family. Specially for my son to have a complete family.

Looking forward for your advice. Thanks and God Bless!

yes he can initiate the petition. the leaving is a matter that will be noted by the court but it won't be a basis for invalidating the marriage. if you contest the annulment, it will have very little chance of success as you appeal it to the Court of Appeals.

realize though that legal remedies may not necessarily help with fixing your relationship

Thank you for the advice.

How about if he file for Legal Separation? Will that be successful now that he lives separately from us?

I'm not planning to file any legal remedies so as not to worsen our situation as Husband and Wife.

if for legal separation, that is possible but you can counter that he is the guilty spouse for abandonment and infidelity