Letting go of my Relationship

I’ve been with my kids father for 9 years now . We’ve dealt with a lot . A lot of lies , cheating , being sneaky it’s just been a tough road that I thought we was getting through together but seem like lately I’m the only one putting in the work . Plus it’s like I will never ever be able to fully trust him . I’ve tried over and over to just let time heal things but I’ve come to the realization that every time it’s time for him to go somewhere or do something that doesn’t involve me I immediately get to thinking about him cheating in the pass , and watching the way he moves to see if I’m tripping or not, and honestly who wants to be in a relationship where they have to watch their own back from their spouse ? Not me ! Only problem is I’m currently pregnant with our 2nd child . Due date is literally 5 days away and I don’t know how to tell him , that I just can’t do it anymore and I need to be more focused on myself and my kids . Thinking about what’s he’s doing 24/7 isn’t gonna get me nowhere !