I just feel like I will never be enough for him. He has been away for work the past month and gets home in about a week.
Well see, that's where your thinking gets a bit skewed.
Truth is, he's proved over and over that he'll never be good enough for you.
He's on affair #3 - that you know of. It's pretty apparent he's a serial cheater since he just keeps repeating this behavior over and over.
Did he make the same promises the other two times you caught him? That he'd never do it again? That he'd respect you and your marriage going forward and never disrespect you again?
Most cheaters make whatever promise they need in order to keep you there. Actually doing the hard work of keeping the promise, however, is impossible for some.
Right now, I wouldn't trust him if he told me it was raining and I heard the thunder outside. I'd still go to the window to see for myself.
He's got a lot of work to do to earn back your trust, if you're going to give him a 4th chance.
Good luck to you, Lotus. I'm sorry you find yourself here.