He's in it with his eyes wide open so definitely a stand up guy. 
I'm in a similar situation myself tho so i might be biased. My two oldest kids are not mine biologically. I claimed them when i hooked up with their mother years ago. We've since broken up after 10 years and i never once thought to turn my back on them after raising them for that long from babies. I guess part of it is also that i know who i'm dealing with, their mother my ex has and probably always will love me and wish we was back together and to that end she has and probably always will have my back if i need her on most things.
End of the day the money spent is a small part of being a GOOD dad....being there and spending time to mold, shape and teach kids is priceless.

I'm in a similar situation myself tho so i might be biased. My two oldest kids are not mine biologically. I claimed them when i hooked up with their mother years ago. We've since broken up after 10 years and i never once thought to turn my back on them after raising them for that long from babies. I guess part of it is also that i know who i'm dealing with, their mother my ex has and probably always will love me and wish we was back together and to that end she has and probably always will have my back if i need her on most things.
End of the day the money spent is a small part of being a GOOD dad....being there and spending time to mold, shape and teach kids is priceless.