DNA, yep it's a match

Is there another Wife out there that has had an unknown child come into your life and say, to your husband,  "You are my father?."   Six months ago it happened to us.  A 39 yr. old woman called, she already had DNA done with the help from my husbands 1st born, not sure how they met.  Also there is a son that my husband said he was not sure was his, he was married to the boys mother.  The son did the DNA too and it is a match.  Who have I been married to for 37 years????  We have gone through a great deal together, I knew we would handle this life alteration too. But, I was alienated, this new person not only came into his life, but it affects me too, and I was never involved with phone conversations.  We live on one side of the country and she lives on the other.  3 hr. time zone difference.  I learned in conversation with my husband he had been talking to her for a couple of months 3 to 4 times a week at 4 a.m. in the morning.  My husband works grave shift.  Their bond was growing.  My husband had a heart attack and was out of work for 2 months.  They never talked.  The day he got back to work he called her.  I believe he pursued her.  My husband has called 900 numbers, remember those?  He has always had porn mags, I never looked for them, I always came across them.   He has invited personal conversations to his email and I had caught him sex texting.  He never calls 1st born, and lately has called son a few times.  But this new DNA, he can't seem to be without her.  I do have trust issues.  It makes all this worse.  We are finally able to talk civil to one another about her, at the beginning it was horrible arguing.  We rarely fought before.  She has brought out the ugly in us.  I asked him to call her on the weekends so I can be involved.  He said he didn't want me dictating to him.  So I told him to choose.  He called her in front of me and said, "I can't call you anymore."  I was shocked!!! Shocked at the little boy voice, - I can't call you anymore. (mommy said I can't) is how it sounded to me, Yikes..... She has not met him eye to eye, yet, but asked today if she could put his name on her birth Certificate.  I'm damn emotional, don't know how to accept this, all of this.