<human>: Could you distill the essence of the text into 1-3 sentences?

Back story:

I started dating my now fiancee about three years ago and over that time, we have been in a long distance relationship (5 hours away). She also has three kids, which makes this work because her ex lives near me, and he pays her gas for drive them to him. During the beginning of the relationship, something happened in my life which made me fall into depression. Stacy, my fiancee, encouraged me to see a doctor about it and get professional help. She was there for me the whole time. I went on anti-depressants and that almost killed me. I reacted severely to them where I either didn't have feelings and didn't care, or was so incredibly sad that I almost ended my life a few times. I couldn't hold a job and starting to slip in school (University). Long story short, I binged on alcohol, abused drugs and ended up cheating. Luckily, I realized what I was doing and snapped out of it before I could damage myself and my relationship. Stacy was VERY supportive, forgave me and took me back every time I went on a bender. I stopped taking antidepressants cold turkey (which I advise to NEVER do) and after recovering, I started coming back to myself.

It's been over a year since I stopped the antidepressants but the anxiety is still there. Stacy has never gave me a reason not to trust her. She has never cheated in her previous relationships (even the abusive ones) and never cheated on me. She is very loyal and a great person. I have a fear of her cheating on me and it causes me anxiety. I find myself acting on this anxiety and doing things that I wouldn't do, like looking through her phone, or ask her questions and over analyze her answers, looking for flaws. If there is anyone who has been through or felt the same thing and has gotten over it, I would greatly appreciate the help. How do I learn to trust her, even though she's never betrayed my trust.
<bot>: I am crazy, I have anxiety about my relationship even though there isn't a reason for it and I need help getting over it.