As a person who have watched countless convert videos and heard their stories, what you are saying is rather a common thing.
Just two examples of people who are well known in the dawah community.
Hamza from hamza's den(youtube channel) was living with his girl friend and even had 2 daughters with her, and as she wasnt okay with him being a Muslim and denied his marriage he eventually married again.
https://youtu.be/4sRPnDFhT_w?t=2195
Jordan from Jordan M (youtube channel)
He mostly does live, so I dont remember which one it was.
Both are married now. Jordan didnt marry for a long time even after becoming Muslim and leaving his past life, but he married very recently Mash Allah.
So about your question...
Is this possible/realistic?
It isnt only realistic, rather it IS the reality of most converts in the west.