I am very uncomfortable with my boyfriend's relationship with his ex. Although they broke up over 10 years ago( due to her having multiple affairs), they have been sleeping together off and on throughout other relationships they have had with people, until last year when I came on the scene. He talks to her and texts her on a fairly regular basis, but not as much as he once did. I like his ex and do not have a problem with her personally, except that she is always sleeping around with people, but have a real problem with the lack of closure in their relationship. My boyfriend says that the closure came when I came on the scene. We just had a 2 day argument over the fact that I would like to know before hand when he has invited her to join us out, as I find it uncomfortable when she suddenly appears without my knowledge. Though this has only happened once, I thought he should know how uncomfortable I was with it. He doesn't have coffee that much with her anymore because I told him that it made me uneasy. He is involved in many activities with her as they are in a carnival band together. He says I have a real trust issue and that they are just good friends. He said to me that she is a really nice person, which to me seems strange because of all the cheating and lying she has done not only to him but with her subsequent partners. I feel horrible but think I am more than justified in feeling uneasy. I have asked for my space for awhile so I can sort my head out. I need some good advise. We have been together for a year but live separately. I am very fond of him. Am I having the wool pulled over my eyes or just being paraniod?

I am very sorry this is happening to you. Feelings of doubt and untrust are going to happen in any relationship, especially with you knowing all do know about your boyfriend's past relationship with this woman. The fact that he has been able to tell you openly about his past is at least positive.
Going by what you have said ( and of course there are 3 sides to every story. His side, her side, and the truth :) ) is it that you believe he is still involved with this woman, or you just want to know if what your feeling is justifiable? No one can tell you your feelings are wrong or not justified. They are YOUR feelings and only your feelings. Never let anyone make you feel like you are acting "crazy" or "paranoid." If you are trying to think clearly and be fair, then you're probably feeling this way for a reason.
That woman friend seems to not understand that you and your beau are serious about each other, and I think she should respect the relationship a little more. The same applies to your boyfriend. I have found in my past relationships (which have been similar!) that when you have that bad feeling in your gut, it means something is wrong.

Be straight forward with him and tell him how you feel and that you need to know the truth, no matter what that truth is.

On one hand he is honest about their relationship. On the other hand your very uncomfortable with it, and that's where the rub lies. To your credit you have not moved in together, and I hope that continues, as there is much more to learn of these two before any decisions, or big changes can occur. If you continue dating him, pay attention to his actions as well as his words. Those you can judge in a realistic way, as if he pulls away from her, to let your relationship flourish, and grow that's a positive. You have every right to be cautious, and should express that in a non-threatening way, and let him make his decision, as to how he handles things, and puts you first before his ex. I think its important to give him the space and trust, to handle his business in a way that put your fears to rest, and gives you confidence in his actions. If not, It makes it rough, and you shouldn't have to settle for anything less than what you deserve. Are there kids involved, you made no mention of any. If not you shouldn't have to worry about her interfering in this relationship, and you should also be alert to any baggage he carries from his life with the ex. Paying attention can go a long way in seeing any red flags you need to know about.