This is a very dangerous predicament. You have just a couple more years left, maybe 5-6, to have biological children and you perseverate in a situation that is clearly dead end. I know it is far easier said than done, but it would be better for you now to take a break from seeing this man.

You said he is also your FP. What does that acronym mean?

Since you have BPD, you probably need therapy to pull yourself out of this relationship and explore more realistic options. Is this possible, to get into therapy? You need someone who can be with you processing your grief over unrequited love.

Is mothering children unpartnered a financial possibility for you?