How to trust again?

The last year has been an awakening period for me. One thing I realized about myself is I am not a trusting person anymore. I've been dating this woman for over a year and I can sense mistrust issues within her as well.

I've was cheated on in my first serious relationship over 10 years ago and my last relationship was with a habitual liar. My current s/o was also cheated on.

She has lots of male friends (expecially ex co workers) who she goes to lunch with at least twice a week. I'd say she has a bank of about 15-20 with maybe 2 of them being female. I have never forbade her or tried to control her in that sense but I noticed that at times depending on how she tells me, I can not help but ask questions about who he is and why. Am I wrong for asking questions and to have concerns. She did tell me little white lies in the beginning of our relationship and done some things to question my trust in her. They were nothing disastrous but they did affect me.

We both have had minor trust issues and have worked hard to overcome a lot of them. I know that if I ever went to lunch or dinner with another woman (friend, ex coworker) my s/o would be giving me 20 questions and get very jealous. I have tried my best to avoid any situation that would make her jealous or cause any mistrust so that I could gain her trust.

Anyhow, if anyone has ever been cheated on and habitually lied too, were you able to ever completely trust someone? How did you overcome it? I know I do trust that she won't cheat on me. I do have rare doubts that she is in a sense, "covering her *** or has a plan B". I constantly struggle the mistrust by building my own self esteem and doing my best to overcome those fears. I realize it is more my problem than hers but there are small things she did and still does that trigger my negative reaction.

THanks for advice in advance