I remember Dr Jekyll & Mr Hyde. One minute abusive & then the next Mr nice.
My advice to you is to keep these texts & start a diary & record this abuse.
My got worse & eventually I couldn't take it anymore & had to visit police with evidence in hand & they in turn spoke to XH.
He still didn't get it & now 7 years down the track when he is taking me for joint custody I have all the evidence I need to produce in court.
As your husband is an alcoholic then he will get worse & so to his behaviour.
Perhaps you can gain some legal advice re. custody? Are there any free public legal services or can you see a lawyer for advice who won't charge unless you proceed?
I am really sorry you are going through this.
Mental abuse sucks & although he has made you feel sick to your stomach, you hold your head high because you are a good person & good mother & don't you forget it. Repeat it over & over in your head when he makes you feel this way.
You can do this.
Big hugs.