Oh, a few more details.

No infidelity that I know of. A few years back, he kissed someone... but I could tell something was up and asked; he fessed up. That's it.

Back in late February, a friend found him on a dating site. He admitted it, said it was just up for less than 24 hours, and that he knew it was stupid but he wanted to feel "wanted." He deleted and hasn't been back on it; said he hadn't even talked to anyone about it. He apologized; I told him I deserved better and that it was disrespectful. He understood but said it meant nothing and was just him being lost and confused.

No kids. We both want kids. He said about two years into the marriage that it'd be too hard and maybe he doesn't want kids anymore. It took me awhile to come to terms with it, but I did. Now, he says he has always wanted kids but just didn't think our marriage was strong enough for it, which is why he said he changed his mind. My sister (3 years younger) getting pregnant was the impetus for him to express his unhappiness because he wants kids, but thinks it would destroy us more than we are already in the weeds.