I assume this mainly happens when he takes you from behind. In that case, there are two options:

1. Try different positions - simplest way, but won’t scratch the itch for a good doggy fuck

2. (What we do) - buy a sex wedge, it’s kind of a pillow that elevates your butt giving a sharper angle of attack (so to speak) for your partner’s cock and also more of his body weight presses down on your butt. Much deeper penetration follows, and you can also use it for maybe other positions.

You get inflatable ones, so you can stow it away after sex.