In my experience, it doesn't get much better.

I've been with my husband 9 years,married 1 year, and have a 2 yr old daughter together and a 10yr old step son.

His mum told me when we first got together that I will never replace my step sons mother, and asked my husband to end it with me. He refused, she didn't speak to us or her grandchild for 2 years.

She didn't come to our wedding, instead went out for dinner with the ex during our ceremony.

Theres sooo many things I could mention but don't wanna rant too much.

It all blew up about 6 months ago and I let rip, since then it's been civil, but still feels awkward. She makes little effort with my daughter but dotes on my step son. He's currently with her at their holiday home and my daughter never gets an invite.

I make an effort when needed. Learnt over the years to not let them get to me, and am generally happier now I'm not holding stuff in and know I can voice my opinion.

Maybe get your SO to stand up for you if there are snide comments and see if he sees what you see when it happens.