I feel like a horrible person and I have no idea how to handle this

I have been working in my field for nearly 6 years and when I started working for this company, I was positioned beside a guy who I ended up getting along with amazingly. The joke is that he's my work husband. We have never ever been romantically involved. We became best friends. We talk about anything and everything and we are good friends outside of work too. We have our lunch together every day, when my mom needed a couch moved, he brought his truck to help out. We go to concerts together, we have similar interests, we give each other advice, we vent to each other, just have a really good relationship. We're too good at reading each other lol. He met this girl probably 3 years ago. And I was honest with him right from the start. She was a bit lazy and an experimental drug user who would rather party than work. And I told him as his friend to just be cautious and that no matter what I'm always here for him. I didn't nag him or anything. Well now they have a daughter and they just recently got married. I've seen her make him happy and that makes me happy. However. She hates my guts. And thinks I'm trying to steal her man on the down low. I'm not. I see him as one of my best friends. I never tested the waters or anything. Now whenever he and her have issues, he immediately comes to me and vents. And no one is perfect and yes there are two sides to every story but sometimes she isn't the nicest person. And I've witnessed it. She cheated on him a week before their wedding yet he still married her. He stopped to get formula on his way home from work and she locked him out for a whole night because she was convinced that he was cheating on her. She locked their crying daughter in her bedroom because she wanted peace and quiet to smoke dope in the basement with her sister. He got her a brand new car so she could get back and forth to work and she quit her job without telling him and she lapsed on the payments and got the car taken away. He's in a messy spot. And he's so stressed out. I've got my own life and my own things of course. I'm actually 35 weeks pregnant with my first baby. No it isn't his lol. But he said to me a week or so ago that he wishes that he and I became something more and that we had a family together and was like he regrets walking down the aisle and is talking bout separating from her and then getting a place with me. I told him he can't say those things and it was wrong. And although he's my best friend,, I've taken a huge step back. I'm not replying to his texts or socializing with him because I don't want to be accused of stealing a married man or being that woman. But now he thinks that I'm turning my back on him and I'm not. I just can't be caught in the middle of something like this! I don't want to have him feel abandoned but the optics of this right now is bad. Help! ****EDIT***** So I can answer some of the questions that were posted. I'm actually not married and the father of my child is NOT in the picture at all. And second of all, I've never considered dating him. I've always seen him as a good friend and as my work husband. I've never thought oh different time different place we could have dated. It seems like an odd thought. I don't like him that way. I care about him! But to date or live with him I have no idea. I think we'd be bad as a couple. It might ruin what we do have