Chronic Stomach Pains

[StingrayPlatypus]

Hi, could really do with some advice here.
I have a stepdaughter, 11, (lets call her Sam) whom I have a fantastic relationship with. Her father and I have been together for 3 years and are engaged. Her and her dad also have a great relationship; they go on regular daddy-daughter days out where its just those two, and as a unit of 3 we get on amazingly.
For the last two months, Sam has had chronic stomach aches. She has been back and forth to the GP, with diagnosis coming back from urine infections to GERD. She has had bloods and urine samples taken, nothing is coming back on the results, everything looks fine. I'm now paying for her to go private in the hopes we can find what the issues are.
Her mum is great with them (Sam has an older brother) but not so good when it comes to men. The latest boyfriend of 4 months moved in after 2 months. He is number 6 who Sam has met since I have been in the picture, and number 10 since her & Sam's dad split. Each to their own, whatever - but I don't understand why they all get to meet Sam straight away. Before they move in, they regularly spend the night. The latest one has two daughters from a previous relationship, they come and stay every other weekend which is nice as they all get on.
I am from a family with a horrific history of SA. I fully accept that this makes me super suspicious and I might be completely out of order. I just do not think we can overlook that the tests are coming back clear, but timing wise, this started when the latest man moved in.
How do I broach this without causing WW3. Are there any suitable films or TV programmes I can watch with Sam where the topic is discussed? Of course I pray I am wrong, pray I am appalled I could even think this. She was at ours this weekend and seemed a lot better, then went back last night and was awake from 1:30am again. The pain is constant, no difference if she eats, worse if she lays down, eased slightly on a low acid diet but was still there. We are still going private. Please can someone tell me I am not evil for worrying about this.

you don’t say that you’ve ever mentioned your concern to her father, your fiance

Hi, I have done. He doesn't think it's anything like that because the bloke has 2 daughters from a previous relationship. I've told him that that doesn't necessarily mean anything, but he thinks I'm being dramatic. That's kind of where I am at, do I back off and leave the parents to it now, or press the issue?

well in that case, you absolutely must just make clear to your dd that you’re there awaits for her

maybe allude to your history to her and you wish you’d opened up

but do not talk to her mother about it behind your partners back

is she an only child? do you have children?

Any family issues of thyroid, gluten intolerance, colitis? My DS 'ins' started around this age and didn't get diagnosed as celiac and hashimitis until his 20's having had years of pain, bleeding etc

But at the same time if you have a bad feeling don't shy away from it, you'd never forgive yourself if you found out later there was something to it. Find some way of making sure she knows she can tell you anything and you will always have her back, no matter what. Maybe prompt with discussions about periods and your plans for having supplies available whenever she needs them but that it's not a taboo topic etc. it introduces an intimate conversation without crossing the boundary to suggest something that may not be there

She has an older brother with her mum, is an only child with us. I do not have children, no.