Ok - let's ignore pretty much everything that's happened prior to now.
Your current situation:
1) You have a very dodgy immigration history - so any marriage application is going to be looked at closely.
2) You're in a relationship with a british person
3) You're planning a family with them.
Ok - so let's say you get married to your new partner. You can no longer qualify under article 8 to get discretionary leave, so you'd have to return home to get a spouse visa.
But also let's say you don't do that - let's say you have a child instead - then we need to look at article 8 in that circumstance:
http://www.ukba.homeoffice.gov.uk/sitec ... iew=Binary
The key bit here is about whether they would remove the person who ISN'T the primary carer. Paragraph 11 seems appropriate.
This says that if you had a poor immigration history (and you do) you might still be subject to removal.
So - all in all - it looks like your best option is to get married with solid proof of your relationship and return home and apply for a spouse visa.
M.