Im 3 months pregnant, should i give up my seat to a late 50s old man whom is standing? While i need to travel long distance and having nausea?

I took bus 66 from little India mrt stn busstop. I'm 3 months pregnant and I was seating inside at the window side. A seat beside me was empty a old age woman 58 plus (from india) came and seat beside me and told me in English to give seat for her husband. I told her I'm 3 months pregnant. She doesnt knows I understand her language she smiled at me and said okay. After that she turn and told her husband she is pregnant. Not even a minute she keep look at my stomach and she look at her husband and said to him as if her stomach is so big she cant stand and give up the seat to you. The husband said it's alright I can stand. I pretended I dont understand like looking through the window. She was totally unhappy and said is it so difficult for her to stand, as if she will deliver her baby right here. The husband kept telling her to stop and it's okay. She continued cursing me. They alighted at Bukit Timah side and I continued my journey. I dont mind giving up my seat if it's a short distance but from little India I need to travel till bukit batok and I cant stand that long having nausea during bus rides. Ps: Her husband is physically fit and doesnt seems so weak. My baby bump can be seen and I was wearing a body shape dress. It's very sad to hear these words from a old woman.