Need unbiased ear to help calm anxiety or provide insight with infidelity PTSD!

Hi all,

Hopefully someone will be able to read through this and give me their opinion, maybe resources to help and hopefully help to calm my anxiety.

Let me start off by saying me and my fiance are due to be married in May this year. We have had a very up and down relationship due to my pornography addiction coming to light over a year and a half ago and the betrayal trauma I instilled in my fiance which I still regret more than anything to this day and have made so many lifestyle changes to help both our recovery. 

My fiance is a gorgeous, loveable, hilarious lady, who gets on with so many different personalities and characters. Through her years, has mainly had guy friends due to the nature of female personalities clashing with hers and preferring to get on with guys instead. She has never once shown any indication of cheating and is something that we have both openly discussed after both being cheated on many years ago, which has instilled a great cause of untrust in myself of all partners since the infidelity took place.

So, cut forward to this last year when she's obtained a job after being a stay-at-home mum for several years to my stepchildren and our now son and has finally found her freedom away from the struggle that is childcare, our dynamic being essentially a 50/50 split caring for the kids. With a job that she works in, they have a pretty sizeable friend group of girls and one or two guys, one of the guys being a very close friend and often go out to the pub after work or after colleague meetings that take place every couple of months. I am glad she has found her freedom but when alcohol is involved, she struggles to see the sensible option sometimes and will often go out drinking instead of coming home from work to be with her family. This does tend to wind me up sometimes when it becomes quite frequent given I would actually like some time with my fiance which is difficult when we have kids as well the tendency to tell me she's coming home at a certain time or has left the pub and won't be long until a few hours have passed since that time and still not being home. I have since told her to stop telling me when she's coming home and have begun just going to sleep and leaving a key out instead of staying up waiting like I would previously.

Now a few incidents are what has driven my anxiety through the roof:

One time I was on night shifts and she was able to get childcare from her mother, she went out with friends for their prearranged outing which lasted till about 1am, she then extended the offer for people to come back to our house and the only person who did was the close friend, the guy in question whom stayed over whilst I was on the night shift - doesn't help with certain children saying things without thinking such as "mum had her boyfriend here staying over last night" when I come home from work

Another situation was when the friend group went out for another night out, in which the invite was extended by him to go back to his. This is after she told me it "wasn't going to be a late one" as any person drinking alcohol does and didn't eventually come home until 5am after I'd fallen asleep 

Or even recently with only a few of the friend group going out and my fiance texting me she's on the walk home at 10pm and not arriving home till 1am, in which I wasn't able to contact her because her phone died which is the reason for her lateness as she went back to close friends and charged her phone and had a few more drinks. 

We're now at the point where they're even getting a similar tattoo together, like friends do, sure, but something about it irks me. It was only when she mentioned she'd be paying a deposit for the tattoo which did eventually come out that it's a deposit because she's paying half for her tattoo and he's paying for his and didn't say that initially because she knows I have this built up anxiety around it all.

We have obviously spoken about all this and she claims they're just friends, understands exactly where I'm coming from and that I have nothing to worry about, she wouldn't have stayed with me after my betrayal if she was just going to cheat, etc. I don't want to overstep my mark because she's easily on the defensive with her paranoid ex who was very narcissistic and run her down constantly

They're gym buddies, they're work buddies, they're drinking buddies and I'm constantly tearing my hair (or lack of) out because of my PTSD with being cheated on previously and am on the fence between it being a justified reaction (I previously had a close girl friend who she used to be funny with because she had an incling that my friend liked me, but we drifted away) or if it is really me, my anxiety and my previous trauma causing me to overreact.

Again, I have no reason to disbelieve her but can anyone give me their thoughts? Are their any resources available to help me move past my previous trauma?

Really appreciate it!