You might try different sizes and brands to see if any work better for you than others. Another option would be for your partner to use a female condom. They are slightly less effective than male condoms but that is primarily because if you slip out there is a risk that you can reinsert outside her sheath. If you do slip out it’s important that she guide you back inside the condom.
Flanders I hope this doesn't sound stupid, but are you pulling your foreskin back before you put the condom on? Just wanted to make sure. I've been with two guyz that are uncirced and that is what we always did with no problems.
You might try different sizes and brands to see if any work better for you than others. Another option would be for your partner to use a female condom. They are slightly less effective than male condoms but that is primarily because if you slip out there is a risk that you can reinsert outside her sheath. If you do slip out it’s important that she guide you back inside the condom.
Good luck
Jill