I am not lactose intolerant but DH is.
When we were dating, before we got married, I made a lovely pasta alfredo with ice cream for desert.
He became incredibly sick, with intestinal cramps, diarrhea, etc.
I didn’t know anything at the time about “lactose intolerant” — I do now.
Fortunately, he decided to marry me anyway, LOL.
Doubtless it was all up hill from there...
Lactaid milk works fine for me! It is also ultrapasteurized, so it lasts forever.