Feeling Confused

I’ve been married for soon to be 5 years and we have a beautiful 3 year old daughter. I suffered a miscarriage in March of 2017 and haven’t been able to get pregnant since. Hubby and I were tested and are clear to start fertility treatments. My problem is this year has been crazy and we’ve been having some problems, problems to the point where I told him I wanted a divorce. We’ve worked things through (nothing related to cheating or that sort) and are together but sometimes I feel like he could be cheating. Work for him is basically meeting with people and doesn’t have a set schedule, I’ve never had a problem with it except sometimes he will go long periods of time without answering a call or even a text. I don’t care that he doesn’t answer but every single time I’ve had to call and text I’ve done with a good reason. I don’t call him to just check on him and he knows it. I feel like he has changed, yes he will tell me he loves me but I just don’t feel like he’s all there in the relationship anymore. I’ve checked his phone and found nothing but he does spend a lot of time on his phone and I’ve brought to his attention. We rarely have sex and he always comes up with the excuse of our three year old and her bed time and gets mad when I make the comment to him that I rarely get laid. I’ve thought that maybe the reason I haven’t been able to get pregnant is because of the problems we’ve had and that we don’t belong together anymore. I feel lost, I love him but I would not forgive him if I caught him cheating and he knows that.