lack of support from SO and feeling alone

Feeling let down and hurt as my partner never defends me. The other week my partner brother in law made some nasty comment about my weight yet my partner said nothing. Then the other day his brother in law was at his work and asked what we doing later and my partner replied we going out for dinner, his brother in law replied Yh bet she gonna eat a lot ( btw I am currently 30 weeks pregnant and finding the. Moment really hurtful atm as my partner says nothing to defend me) not to mention that he been nasty comments about how he thinks my baby will be a monster as he is measuring a bit big already 3.7 lbs going by my last scan the other day. Mayb I'm just being over sensitive but it hurts feeling like I got no support from my SO