My [46 F] husband [ 4 M ] of 25 years had baby with another woman and now that baby is in my house!

We had been married for 25 years. Our relationship had never any big issue. We have two wonderful kids together.. I am a proud mother. Everything was amazing until this....
My husband brought the child in my house. I was bewildered when I saw the baby in my house. I thought for a moment , maybe some guest came to our house.
He called me and said , " Ummm.....he's a baby of Mark [ our friend , not real name ] and he has gone to France for a vacation with his wife for almost a month. So he left his baby with me since he trusts us. " I was like... " What? They could have taken the baby with them. And why- " My husband interrupted me , " I understand you. But he is our precious friend and he wanted to spend time with his wife without distraction so we have to do this now. "
A baby is a distraction? Wow. I immediately sensed that something is really fishy. I thought IF he had the nerve to bring his illegal baby inside the house then no words can make the difference. I said okay to it. It was killing me inside.
In the night , when my husband went to washroom , I immediately picked his phone to check his messages. I knew it was wrong to see the messages but the curiousity was killing me. I searched for Mark and went to the conversation between him and my husband. I gazed through messages for 30 seconds and did not find even a single text about a baby. My husband unlocked the door and I had to put his phone down and prentended like nothing happened. We slept together then.
After a day , my mom got really sick so I had to go to hospital to see her and stay with her for few days. Talk about bad timing. I told my husband that I'm going to my mom for about 2 weeks and went off.
In my heart , I knew it that maybe our marriage is over. I had 100% gut feeling that Mark would never do something that stupid and my husband reasoning seemed very lame.
I went to my mom and she seemed very sick. I did not tell anyone about this. My sister with whom I share almost everyting asked me that if something is off? To which I said that I am fine.
I texted Mark to ask about the baby. He replied to me after 16 hours. 16 hours felt like 2 weeks , I swear. When I got the message , my heart was pounding so fast. It was almost 2AM and everyone was sleeping.
I went to washroom to read his text. Oh God. The worst happened. My heart was broken so badly. Mark's baby was with him. I started crying but in my heart I knew it already when he made a lame excuse. But what broke my heart is that he actually had the nerve to bring the baby to our house. What a ****ing moron he is.
Its almost 3AM here...and I am in toilet for like 40 minutes and I am crying like a baby. My marriage of 25 years is destroyed. I don't want to see my husband's face ever. I don't care that who is the mother of a baby. I don't even have a question for him. I just don't even want to talk with him. But I think...Why? Everything was amazing.
What do I do with my life now? Here my mom is really sick and now my husband cheated on me. My life has turned upside down in couple of days. I want to ghost my husband and get divorce immediately. Oh people....what do I do?
TL;DR: Been married for 25 years. Husband brought the baby in our house saying " it's our friend Mark's child " since he his on a vacation with his wife. I didn't believe and suddenly my mom got sick so I went to her and meanwhile , I texted Mark to actually ask him about his baby. He said that his baby was with him. My heart broke and now I am crying in a washroom thinking what should I do now?

---

Edit : I've decided to talk to him about the baby and the mother. I honestly don't think that I can even tolerate his presence or talk to him on phone but I guess I should clear the things out. Hopefully everything works out!
And I honestly don't think he'd ever kidnap the baby. I'm pretty sure it is his child. He was very affectionate with him. Things will be clear soon!


Source.

Dang her husband is only 4 yrs old, she's a cradle robber lol