thats pretty weird no offense
it depends on the circumstances. for me, enjoying such a particular thing would be an activity I would reserve for when I am married someday. It'd be a private activity for my wife and I could enjoy when/if she and I choose to have a child and she becomes pregnant.
it wouldn't be something we'd like make awkward by "scheduling tummy sessions" or something weird like that. It'd be more like, she and I wake up in the morning, I wrap my arms around her, we hug, I pull her close, her belly is in full physical contact with me, I kiss her, and I lean down and kiss her on her tummy, and compliment her on how thankful I am to have such a great wife and how good a mother she is going to be :)
and certainly compliment her that she is the most beautiful and attractive pregnant woman in the world!
then I go fix her breakfast <3
In the broad scope of things though, I really don't think this is that weird or gross a thing to like. It certainly would be an easier and more comfortable activity for my future wife and I to enjoy than say, things that could be more uncomfortable, like bondage or brown town love. My kinks are rather harmless ones.
besides, pretty much all girls like foot rubs too. and imagine all the shoes she'd be able to get!