L.C.
Oh Sweetie,
PMS is nothing to blow off. I can tell when I'm going to start my period because I want to eat everything not nailed down, everyone in the house starts breathing too loud, and I cry at shows on the Food Network. Then there's the first two days of my period. More of the same plus a little bit extra.
And when I got pregnant with my fifth child? My oldest offered to start a prayer group. Not for me, but for those that had to deal with me.
Probably what would help your husband the most is for him to hear it from someone other than you. Perhaps if he went to the OB/GYN with you and heard it from a physician. Then there's his mom or a sister or a cousin. Maybe just to make a light little joking way to do it you could have all the men you know (brothers, friends husbands, whoever) write up their worst PMS, pregnancy experience and make it into a little booklet for him. Kind of the man's version of "What to Expect When She's Expecting...and When She's Not." That way he could see it's not just you and it's not just him and maybe other people could help give him ideas of what HE could do to help you.
Whatever the answer, he can get glad in the same pants he got mad in.
L.