Why do 'things change' when you go from friends to lovers?

My husband and I were very close friends before we got serious. I never hung out with alot of women and was always a bit of a tomboy. I met him in the military and the man to woman ratio is like 3-1 so of course the majority of my crowd was guys. Me and my now husband ran with the same crowd. It would always be me, one oter female who is still a very lose friend of mine now and about 2-3 additional guys not including my husband. They treated us, me and the other female, like one of the guys. We all talked about intimate endeavors, got drunk together, told jokes, laughed, went to luvs and bars as big groups and they were also our protectors. They were like a pack of big brothers. Whatever other intentions they may have had we're never spoken of. After a while, my husband and I stared to notice we had way more in common and enjoyed many more laughs when it was just us. One thing lead to another and the rest is history :) that being said, some of those same friends would invite him to hang out and he wouldn't want me to tag along. He Los expressed he oesnt really like me to wear make up or leggings as pants or shorts ths are too short. I don't care, he's my husband and I love him. I think it's cute because he's not demanding. He expresses his feelings and I do my best to accommodate. I'm just wondering what in the make mind changes when your best bud becomes your wife?