My husband didn't come home last night...?

For the past 2 days,my husband came home late and now he didn't come home at all. Last month he had been doing this and I talked to him and he stopped for a week then he would still do it every now and then. I'm pregnant with our first child and I told him not to do this since I can't always sleep whenever he comes home late or not at all and I don't want to be stressed out bec of the baby. He would still do it and now again. I told himI want out if he keeps on doing this but to no avail. He said he's not doing anything and just going out with friends(drinking). He had an affair with his co-worker 6 months ago and I've forgiven him. I'm afraid he's recently seeing her again or somebody else. What should I do now? I think he's not taking what am telling him seriously. Please give me a sound advice. Thank you.