I had an infant and toddler when I found out and I think that was the main reason I was even willing to try to save our marriage when I found out. I was so hurt and at that point I couldn't see me ever trusting him again but because of my boys I wanted to make sure I did everything I could to make sure.
It was hard, that first year was probably the hardest thing I've ever done. I think you need to focus on your H's actions, is he doing everything he can to ease your mind, make you feel safe in the relationship, and showing you that he is trustworthy? If the answer is yes than you have a lot to do to start healing yourself. I say that b/c in my experience a WS can assist you in healing but they can't fix you. I think that first year I started getting mad b/c my H wasn't fixing me, healing me, he can't. I had to see an IC and work thru the issues my H's affair caused, but I was the only one that could fix them ( sudden insecurity, unwillingness to trust/fear of trusting, anger, resentment and wanting to punish him) those are all things our WS can't fix.
So if your H is showing you, not telling, words mean nothing, but truly doing whatever you need to feel safe then the work starts with an IC and possibly MC if you need help learning how to communicate and sort thru issues. If your H doesn't know why he chose to have an affair and doesn't know how to handle boundaries with others or how to deal with whatever issue lead to his choice, IC for him for sure. Even if he says he'll never do it again, no way! if he hasn't dealt with what got him there in the first place, it's going to happen again, b/c he doesn't have an alternate way of coping.
I am positive a marriage can survive infidelity, we are doing great at 6 years, but it was really hard work, both people have to want to save it and make it better and be willing to work thru the bad stuff not "put it behind us" but face it head on and deal with it all. It's worth it, our marriage is better and I'm happy and he's happy and the kids are happier having two parents that are committed to each other and them, we weren't like that before the A, we were a mess but I didn't realize it at the time.