Should a wife push herself outside of her comfort zone in the bedroom?

Hubby and I have been married 13 years. He’s a good guy, we’ve had some things we’ve worked through, but generally things are good (and busy with 3 young kids)!

However, I’m struggling a little bit with how to approach it when I’m uncomfortable with a sexual act he wants to do. We have a pattern of him asking, me nicely saying no usually 5-6 times, then eventually I give in and it just doesn’t feel great. The last time it was that he wanted to be on top while I give him oral and the feeling of being trapped (even though I wasn’t trapped) was just too much and he found out I had been crying in the bathroom after. I cry super easily with any feeling of overwhelm, it’s not like it was traumatic, but it was something I knew I wouldn’t like doing before trying and felt a little hurt that he keeps asking knowing I don’t want to do that thing.

Now there’s something new on the table again and I’m nervous to try it. I get that after 13 years of doing all the normal stuff it’s probably exciting for him to try new things, so I don’t want to be selfish or boring. How do I know how far to push myself without causing negative feelings? I am also trying to work through feeling some resentment for the fact that sexually I do about 75% of the work and there are often nights I am tired but still put in the effort when he’s in the mood. I enjoy sex, but there are often nights where it still feels a bit like a chore, even though I feel bad saying that.

We have very regular sex, I can only get there one way, but we do switch it up for him. I wear lingerie on Saturdays (our in-house “date night”), so I don’t think I’m being too reserved, but I also feel guilty when saying no to trying things. Would love advice from maybe some older couples who could share some wisdom?!?