This is embarrassing, but since i've been cheating on my husband with a bigger man, i notice my vagina lips are loose and have stretched. if there anyway to be tight again so my husband doesn't find out, if i ever go back to his micro peen?

Any penis bigger than your husbands will cause enlargement of vagina tissue. Solution find a man with small penis or stop cheating.

No there is not. Your actions are your personal matter and you alone can decide what is right and good for you

You may try Kegel exercises, though that will not directly affect the labia but may tighten the vagina. Depending on the level of your concern and resources, a plastic surgeon could refashion your labia.