The first sign of my xabf cheating was simply my gut telling me so. I had zero proof. It wasn't like he didn't call or text as much or was making excuses not to see me. He answered my texts and calls immediately...he still wanted sex all the time, he was always around. Always overboard with affection and attention. In other words, I had no reason to suspect it whatsoever, yet SOMETHING continually nagged in my gut that he was cheating. I couldn't tell you how, I just knew. And sure enough, he was. It reminded me a lot of my alcohol detector. I think I even have a thread out there on this somewhere. I knew many times when he was drinking even though I had no evidence and nothing he was doing was typical of drunk behavior. But there would be the smallest subtleties in his ways. Again, zero evidence, but just SOMETHING in me knew. And sure enough, there I was also correct.
The things is, is that when we don't have trust in a relationship, it is really hard to have a relationship at all. I never had trust issues in past relationships as I felt confident and comfortable that partners were faithful and honest about other things, and to my knowledge they were. I only started getting gut feelings and doubts in the relationship I had with the addict. That to me was a sign that I simply could not trust him in any regard because he violated trust on so many levels. Whether it was lying about drinking, other women, or trusting him not to come over if intoxicated, each time I was repeatedly deceived despite always giving benefit of the doubt. What I learned is that it wasn't about me. I truly believe he loved me and cared for me, but simply did not know how to respect me (nor himself). He put his addictions first as addicts do, and put his own self worth last so you know mine was then dead last. I loved him, but I could not trust him. He loved me, but could not respect my trust. It was always about him and his need for instant gratification to somehow quell whatever was inside him he didn't quite know how to contend with.
Try not to obsess too much over this (easier said then done because once the thought got in my heads that's all I did was obsess until I found out!). In the end a man who doesn't respect himself will never be able to respect you. Addicts tend to not have much of that while in active addiction. And it's nothing to do with us. Let it go and accept not knowing. You may be better off.