I think your ideas about their relationship (and how they saw each other) sounds about right. It feels unlikely they would actually have had a child together, but if they did, could a love potion be ruled out as a possibility (Bellatrix using it against Voldemort)? Voldemort couldn't feel love, but a love potion doesn't actually create a feeling of love, but more accurately a feeling of obsession. It doesn't really seem like Voldemort could be tricked into taking a love potion, somehow, but I don't know if it could be definitively ruled out based on information (or lack thereof) that we have.

Right, I thought of adding a possible theory of Bellatrix giving him a love potion, but I decided against it because it would be very slim for him to fall for it.

The cursed child is considered canon, also it only worked because Voldamort did it to reward bellatrix, which goes to show how evil he really is.

I think the love potion thing is not really something that would happen.

As others have pointed out, it is very unlikely that Voldemort would fall for it and I might add that Bellatrix wouldn’t risk it for several reasons: the first and the obvious one is that despite her obsession for her master, she also deeply feared him and I don’t think she would risk invoking his wrath in the very likely possibility she was discovered; the second reason is a bit more subtle but present nonetheless and it is that Bellatrix has way too much respect for Voldemort (considers him the greatest wizard of all time) to do something as sneaky as this with him.

While I think the whole notion of Voldemort and Bellatrix having a child is highly unlikely for both mental and even physical reasons (I’m not fully convinced Voldemort’s internal organs even work), if it we absolutely have to say that it happened, then a far more likely scenario would be that Bellatrix, obsessed with both Voldemort and blood purity, would insinuate the possibility of a child with him and Voldemort, proud of his lineage, would grant her the “honor”.

I think he would have viewed Delphi as just an extension of himself, an audience for his grandiose ego, and maybe would even turn her into a horrocrux at some point.

Hehehe internal organs that don't work

Oops, was it because i stabbed those internal organs? /j

Maybe if bella did use a love potion on voldy, she could have put it in his water or whatever he drinks lol

I dint think they did it out of love

Voldy wanted an heir and knew bellatrix would do that for him