Hi Open soul. I think compromise may be key here. And some toleance and understanding on both sides as well. First, she is your wife, so you dont jave to trust her friend's intentions but you should trust your wife's if she says nothing romanticis going on and other than the close nature of their relationship you have no proof. I doesnt sound like she is sneaking around or hiding anything from you at all. I have had to give up some good trusted friends cuz my husband was very uncomfortable w the fact that some of them were exs, and that i am not really goid with group stuff so i tend to hang out with my friends indiviually which he found inappropriate both because they had been exs and the nature of my friends in general (and this is going all the way back to teen yrs when i did better in groups and most of these exs i had known most my life, also i am soeaking earlier on in my hubbie and is relationship so 5-10 yrs ago) My friends are all nighter sometimes to 3day kinda people. So he had issue like you with me going out with my friends and honestly just planning on hanging out for a few..but ending up disappearing abd showing back home the next day or whatever. To me this was natural and there was never anything more than friendship going on, but from his,syand point unacceptable behavior. We had very simular arguements infact diwn to the wording as you and your wife... We are older and different people now and we both now can see where we both were wrong and right. Wish we could have been able to compromise back then..so i hope that you and your wife can work out a matire comprimise save you both alot of resentment anger and snowballing trust issues. IMHO... it seems like this person is besides you prob your wifes closest bff. Everyone needs a best friend and while married your SO is your best friend still you need an outside bestie to be able to vent healthly about your marriage to and just talk about stuff that is not married stuff. So its really not right to ask your wife to cut that friendship out. What your wife needs to understand is that when you get married it is not like getting an awesome roomate w benifits, it is now your primary relationship, friends come second. Not that they are less important but they are external from your bond and you need to feel that she puts as much effort and time if not more into ur marriage as she dies her friendships. So she does need to accept some boundaries. Acceptable boundaries are that unless there is some serious bff emergency showing up, calling, and going out at the drop ofa hat in the middle of the night not ok. There needs to be a bit more distance and planning. SO time and friend time need to not constantly overlap. If you and her are doing your thing she should not be pushing you aside to have long chats with her bff, except on occasion. If the two of you are having a night together and actively doing something together then call should be ignored and returned later or quick text or whats up and then inform her friend that she is not available tonight sheis spending time with you. You in turn need to allow her to talk to her friend and have time to spebd with her when you are either both just doing your own thing and if she makes plans to go out with her friend 1night a week you cant really demand a curfew. She is,an adult and as long as there is not something pressing that she needs to be rresonsible about the next morning... and its not like multiple times a week but once a week to once a month if she wants to go tear it up with her friend til dawn, you gotta decide to trust her and you are not her warden or her father, so treating her free time as something that you have,a right to manage is conveying that you dont trust her or her judgement and really that you dont view her as an equal adult. Nonody is gonna respond well to that. But if she is showing up at 4am falling over when the two of you have early plans or responsibilities the next day...then that is inaappropriat and disrespectful to you and shows,a general lack of self control which is a whole different matter. But wait til she is sober and in a good space to tell her that is not ok with you cuz arguing with someone who has been out all night is always pointless. Approach her gently and kindly and tell her you have some stuff you want to talk. Validate her and her friendship, then tell her calmly and nonjudgementally your absoult dealbreakers, not minor worries or issues just the biggies..explain how you feel and that it not blame or an accusation then say that you want to figure out a way to end the conflict but need something to change a little bit. Then ask her for suggestions of what she needs and feels is fair and what she is willing to give. If you approach the conversation from a place of love and desire to make your marriage better, and still her have room and time for her friendships...hopefully, with a little bit of give and take from both of you...the conflict may become more tolerable. Sorry this is so long and overly worded. My mind is not at its best lately. But i hope that some of it helps wish you all the best.