Is vaginoplasty after childbirth to improve my husband's sexual pleasure permissible?

After having a child (where the delivery was normal) my husband is having a hard time fulfilling his sexual desire with me; not because of outward appearance, but during sex when he is inside me. There are surgeries available to help fix the situation: > Vaginoplasty is a procedure that aims to "tighten up" a vagina that's become slack or loose from vaginal childbirth or aging. -- WebMD However, I'm not sure if these types of surgeries are halal (due to necessity) or haram. I have also noticed the change with myself and feel very depressed and embarrassed by this thing. Please, I'm seeking the most correct knowledge on this situation.