These situations are always difficult for all involved. Myself I have been married twice, once young and then again around age 30 yr old. My first marriage lasted 4 yrs, whilst my ongoing marriage now, is 30yrs so far. My wife was previously married young and divorced at 5 years. We have two adult children who are both now doctors, as is my wife.
When people get married young, then the unknown can be seen as 'exciting' .... Whereas in truth it may be exciting or simply awful; because all it is, is unknown. This is what happened to my first wife, she felt she was 'missing out' after three years she realised she wasn't but I would not take her back. Myself I am not emotional and she had broken my trust. In truth the greatest thing she ever did for me was leave .... It opened my eyes to work possibilities I was missing and of course eventually led me to my amazing wife whom I both love and am in love with, as she is with myself.
Whilst you have your own lives, both you and your husband both have a responsibility to your children until they are 18yr old ... After that they are adults (hopefully you have brought them to be adults) and your life is more your own.
Considering your present situation I personally cannot imagine more children is a good or even passable idea, indeed I would advise against it entirely - New children never remedied an old relationship.
In truth you are looking for an answer that is unknown ... if you leave and get divorced will you find love. My personal experience was "Yes" but I know just how rare my wife and I are. We are both unemotional pragmatic people, we had baggage but dealt with it all together, from day one we have done everything as a single unit, not two people in a relationship.
It seems that most people leave, meet a whole load of other people searching for a new life and at best end up with mostly what they had before .... You have to understand that wherever you go and whatever you do, you take yourself with you, you have not changed. In my view you are still thinking like an 18yr old and that is understandable but maybe not helpful.
Whatever you do - no more children. Not unless you are 100% happy and settled with someone, your present husband or someone else.
After that .. only you can roll the dice. Good fortune to you
PS ... Do be aware in any relationship if they will cheat to be with you, they will almost certainly cheat on you.