As others have said there is a lot to weigh up.
Humans and relationships are complex.
Building a secure relationship is a process.
Given your orientation, the most secure relationship with your GF it seems to me will be built on "unity in Christ" (the gospel) instead of "unity in doctrine" (religion).
I wonder if your GF would be willing for both of you to patiently explore the liberating (unabridged) gospel (according to Paul) in her own publications?
DF or not, if she remains a captive of the Watchtower/religion, your relationship will never be secure, and your children will be highly vulnerable.
PM me if you'd like a 1-page summary of the gospel in their publications.
Yes, it can be found in their publications, albeit in fragments.
Tellingly though, the gospel is not in their hearts nor on their lips.
Blessings
Fernando
South East Queensland, Australia