i am going to speak from a child's perspective (by "child" i mean - being only 20 and growing up with fighting/cheating parents but also coming out of a very bad relationship.)
first off, growing up with parents who fought CONSTANTLY was a nightmare. i was always in the middle of everything, blamed myself, felt guilty, witnessed and heard horrible things. i do not have a clear vision of what love is. i feel as though my parents should be divorced but aren't "for the kids." if you do not have children, i definitely suggest you taking time apart and figuring it out. it is so, so hard on children when their parents are leaving, cheating, fighting, screaming and not trusting each other. my parents talk to me about their marital issues, talk to me about each other, make fun of each other to me - figure this out while you don't have kids. you are very, very young and if this situation may affect the rest of your marriage/life - throwing kids into the mix will only make it harder. i understand parents have it hard too, but i don't think anyone realizes how hard it is for the kids.
- i have witnessed both of my parents cheating on one another. i hear about it, i know about it, i have read it. its terrible. i am finally in college now - away from home, but my younger brother is still home. he is my best friend and i hate that he has to deal with this alone. my dad is always traveling for work (but also doing who knows what), my mom is sketchy and has her own mental issues - basically, its a messed up deal so fix it while you can.
secondly - i am young but i just came out of my first relationship. if you bring kids into it, raise them in an unhappy household and expose them to that behavior, it can really mess them up. i don't trust people, i can fight about little things, i am jealous and was constantly worried about what my partner is doing. i became codependent, i did everything for my partner because i wanted to avoid fights so i was emotionally/mentally/verbally abused, taken advantage of, cheated on and completely screwed over. i cannot tell you whether or not to leave him. no one in this room can. people say once a cheater, always a cheater. i don't believe that. i believe in learning from mistakes. i don't think its right to keep secrets. i DO think you should walk away for a little bit and take some time. set your boundaries and set your rules. if you don't want him talking to her SAY it. let him know you won't deal with that or accept cheating to be okay. let him know what he's missing. show him that he can't mess up and be forgiven that easily. when you walk away, he will have two choices - prove that he loves/cares and wants to be with you or he will prove that his heart is in another place by his actions. if you walk around not trusting him all day, everyday, it makes for a miserable life. say what you want and outline a list of things that will make YOU feel more comfortable and at ease in your head. if you don't settle this issue with yourself - you'll constantly fight with him, mistrust him, call him out, snoop and eventually you will have lost control. take time to figure it all out and make sense of it YOURSELF and then fix your relationship. you are most important.
sending good thoughts your way. stay strong and know that it does get better.