I would share my feelings with my partner if I felt that anything was going on. I always try to be open and honest with my those in my life, otherwise, feelings start to build up and tensions start to rise.
Have you thought about going to couples therapy so that both of you could speak about your feelings? Trust is very hard to regain, and perhaps a professional can help sort of feelings that are warrented and feelings that are just arising from the past? Sometimes it is hard to assess a situation when you are in the middle of it and there is past history.
There is no way to read your partners mind, so unless he is willing to open up and be honest, you will never fully know if there is anything going on. I would try to look at the situation and decide if it is healthy to spend so much time and energy on worrying about what he is doing, who he is talking to, and what is going on in meetings. Try to focus on yourself, and get yourself in a healthy spot, emotionally and physically.
If you express your feelings and he decides that this is the way he wants to act and behave, well then you will have to decide if this is the relationship for you. The reality is that people cheat, whether they are sober, actively using, in AA, at work, or anywhere. Whenever someone is in a relationship, there will always be a chance that an affair could occur, and you have to decide if you don't that you are being respected and treated properly, if you should leave.