When to end a marriage and how to get to the true story?

[AtTheEndofTheRoad]

I posted last summer about how my marriage essentially pretty loveless, which i realised pretty suddenly. It was as if the scales fell from my eyes.
I decided not to do anything drastic immediately as I the oldest DC's are in exam years and I am very worried about screwing things up for them.
Since then I have had several discussions with him- which mostly consist of me saying what I think and him making minimal response, but then when I try to talk to him again saying; " I thought we'd sorted that out".
We had a very distant 4 months between June and November when he was finishing a course ( one of his interests, not related to his job) and he obviously put me on hold.
i have found out that when DC2 was a new baby, between 0 and 6 months he either had an affair or didn't because she said no. I was on my knees with tiredness and lack of sleep and he offered no help at all; just pretended he was single for a while.
My question is; if he behaved like that then, is it likely to have been a one off? Or is he likely to have done the same since? Would that explain the periods when he has been unaccountably horrible for no reason I can see since?
I'm sort of beyond grieving and being angry. I would just like to get to the truth.

Did he tell you about the possible affair? If he's sone it once he could have done it again. If you know you are going to leave once DC exams are finished does it matter? Or are you hoping to salvage a relationship with him?

Don't worry about DC's doing exams. Mine were doing GCSEs and A levels when they found out we were divorcing. They got great results because ex had gone and I was happy.

It would fit a pattern. But unless he confirms it you're never going to know for sure.

Are you saying you suspect he is having an affair/has had affairs? Please be aware you may never know the truth, certainly not the whole truth anyway.

It sounds as if your marriage is over anyway eg 'loveless.' How important is it to know if he has had affairs anyway? If you don't love each other, that is reason enough to end your marriage.

Do you want to start making plans to separate or divorce?

I loved him until the day in June when I suddenly saw in his eyes that he didn't love me. It's not really important except it would explain why he has been horrible at times. I'm sure I'll never know the whole truth. But I was thinking if someone has started in that pattern would they be likely to repeat it. I made a statement to him of what I strongly think happened and he didn't disagree or correct me. Just asked why I was going over something that was years ago.
Perhaps it doesn't matter. He doesn't want to divorce- he wants to stay married. He thinks I am unreasonable to expect love after what is already a long marriage. I'm not saying I need raging passion, but I think affection, kindness, empathy, respect are reasonable expectations. He also doesn't want to take the financial hit of splitting.
I think I want to separate, but the logistics of doing so seem intimidating.
When he's away the mood in the house is immediately happier, so I get what you're saying Savage.

You are right, those are reasonable expectations. Have you had advice on the logistics or are you basing on what you know and he thinks? It's the rest of your life you are talking about. Don't give up being happy because the road to get there is hard. Whether you work it out with him or strike out on your own. Get advice.

What good will the truth do you? You seem to feel the need to justify wanting to divorce to him - you don't have to do that. All you need to say is that you want to split and that's it, the decision's made. He can't force you to stay married to him.
He doesn't want to split because he can't be bothered. Giving him a 'good' reason won't change anything.

That's it I think. I was brought up to think you stayed married come what may, but now I'm thinking- is this it? And I only get one life, so why waste it. Thank you all.