He hasn’t said it outright but I know he doesn’t like it. I don’t either but in the past he had a minor operation that resulted in a lot of scar tissue once everything healed up which was causing him discomfort. I made sure to massage the scar tissue often to help ease the pain. I know expecting things to be returned isn’t always great but I’ll admit I did expect him to give me the same treatment.
This would be a good thing to just state clearly to him. "I know you don't like giving massages and I understand as I'm not much of a fan either, but I did it for you uncomplainingly when you needed it to help ease your scar pain so I am hoping you will return the favour now that I need it. This pregnancy is really hard on my body and I'm struggling. Can you help me with this?"
It's not unreasonable at all to expect give and take in a relationship. Give and take is normal, workable and a part of any healthy relationship.
His response will tell you a lot. If he dismisses your contribution with something like "Well, I never asked you for that and I would have been fine if you didn't do it", you need to understand that you may be doing things for him that you think are nice but that he doesn't value and see as you contributing to the relationship. That will lead to resentment on your part.
You could ask him, okay, if that's not meaningful to you, what is meaningful to you? Can you think of sacrifices I make for you that are meaningful and would motivate you to care for me in the ways that are meaningful to me? Like how I watch football with you even though I am not into it but know you love it? Like me making you dinner and doing the dishes while you relax, even though I am very tired with this pregnancy? I feel I am contributing a lot to this relationship and to your happiness, but it needs to go both ways.
Maybe this will be the wake-up call he needs, but also maybe it's a wake-up call for you to see that you might be martyring yourself for someone who doesn't actually appreciate what you bring. That's a bitter pill to swallow and something that's easy to deny to yourself or convince yourself that 'it will change in the future'. But you can waste a lot of years and energy trying to earn someone's love through actions that they don't value.