OP, this sounds like a real mess. Your H has continually lied to you, he hasn't lifted a finger to try and right HIS wrongs or work on the marriage. He seems to be paying just lip service. You seem to be grasping around for anything that means the heat is taken off him (i.e. "my H is weak, has no control....OW is manipulative etc"). I think you're trying to look for anything at all, any hope to try and save this marriage.
I honestly mean this kindly...he's treating you with contempt. He's treating you - the woman that he swore to love, honour and be faithful to - like absolute shit. From what you've said, it looks like you're pinning hope on him not seeing OW at all during this 5months of leave and therefore he'll forget about her. But how do you know that he'll not sneak out and see her? Or message her/be in contact with her? Or sneak off and find someone else? I don't think that you will find peace of mind with this man. The worry of what he is doing and with whom will not go away and I'm so sorry that this is happening to you.
Can marriages/relationships survive infidelity? I know of two marriages which have: both couples are good, very long term, friends of mine. In both cases, the guy in each couple had had an affair with an OW, but the guy had confessed (not left it for the spouse to find out). Both guys did the work needed to get their relationships back on track: that included changing jobs, moving, counselling and being completely honest with their spouses (and also with family and friends). They both ran the gauntlet and did whatever it took. They also did this knowing that at any point, their spouses could end things. As friends looking in on these situations, these guys would have been the last ones on the planet that we'd ever assume would cheat, and we were shocked by it. But the guys were open, upfront, blamed no one but themselves and did everything they could to try and resolve things.
My marriage didn't survive infidelity (but it was on the rocks anyway due to XH's other behaviours - finding out about him and OW was the nail in the coffin). I filed for divorce and didn't budge on it, not even when XH tried to come crawling back when he and OW split. What I can promise you though, is that if you don't have trust or peace within your relationship, then it is a stressful, miserable and very lonely place to be. I became a shadow of my former self, and I made myself ill: I thought I was going insane from all the gaslighting and shit. I miss the man I married (not the one he turned into!) but I would rather stay single forever than even risk having my peace of mind affected by another situation like the one I was in. The calm and peace I have enjoyed in the years since my marriage ended is priceless, and life is good (I'm a single parent with 2DC). Please look after yourself, at least get some legal advice so you have a better idea of things and can make some informed choices. I wish you lots of luck