OP. Glad you are 'back' - or at least reading all this - here it is, this is what other people think. No matter what you think of it, it has value, as when you're the person in a situation, firstly you don't have this perspective, and secondly you tend to want to wish it away, minimise it. So - I'm sure this is all painful to hear but I really hope you're listening to it anyway.
One of the main reasons I think you've had such an outpouring of indignation and strength of feeling on here - it isn't just that he's clearly a dodgy fucker - it's that the stakes are so high for you. You don't say how old you are. But it's one thing to be with a dodgy fucker, and quite another to give up your chance of having children, a family, to be with said fucker.
The bottom line is, this is not a faithful or honest man. This is a man who puts himself first, who is prepared to lie and deceive.
There are many people who would, for a million reasons, be prepared to stay in a 'bad' relationship, because of the other stuff they get out of it. Security, family, whatever. And it's hard to judge what's the best option unless you're in it.
But I don't think you'll find a single person who would say that, if you are a person who wants children, wants a family, that a dodgy, faithless liar is worth giving up your chance of that. There truly is nothing in this for you - just him, and the him he's shown himself to be isn't worth having. And you now know that should he ever get a better offer, he'll be out the door (or simply shagging behind your back) without a second thought. How would you feel if you 'worked it out' this time, stayed, ended up childless, and he left you high and dry at 50 for a twentysomething work colleague?
The bald truth is that because the infertility is his problem, the sacrifice you're already making is HUGE. He's so clearly not worth that, that a hundred odd women on here, many of whom know the incredibly huge part of life you would be missing out on to stay with a shit, are queuing up to howl at you to get out.
It's fine to be stunned, anyone would be. Take your time. You don't even have to do anything re the texts - you know what you need to. But please please read these posts and really think hard about walking away when you have the strength to do so, and don't waste any more time.