Need serious advice

Okay I am going to leave a lot out to hopefully get the point across quickly. I've been with my husband for almost 6 years. We have a 1 & 1/2 year old daughter and we are due to have our son in less than 3 weeks. We have had a lot of issues in our relationship. The majority is him lying and keeping secrets. Even weird small things. I've caught him talking to other girls many times but as far as I'm aware, he hasn't since we married in july. I know I'm setting myself up for failure. I dont need opinions on the choice to stay with him. But here's my question. I've reached the top of a waiting list for an income based apartment. I will likely not have to pay rent considering I dont have a job atm. My husband and i have talked about it and would only do it to live separately while going to marriage counseling. The plan is to wait until he finishes school in the summer to buy a house. And use the time living spart to better ourselves and pur relationship. Is this a stupid idea? Are we just dragging out the end of our relationship? I'm at such a loss. 💔😭