I’m pregnant (25F) and my husband (26M) wants a divorce

I'm currently 17 weeks pregnant. I've been with my husband for 10 years, and we've been married for 3. We've been going through a rough patch for the past year, but I thought everything was turning a corner. He told me four months ago he wanted to have a baby with me. I said I wasn't sure if we were ready, but we tried and get pregnant on the first try. Three weeks ago, I found out he had a secret girlfriend and I kicked him out. The next day, I told him I wanted him to come home and work it out, but he refused and still refuses. Still hasn't been home. He said he’s going to file for divorce. Even through everything, I still want to try and make things work. Any ideas on how to convince him to come home while still not trying to be consumed by grief so I can take care of myself and the baby?