In reply to broady: As a general response to all the thoughts that have already be made, I understand how partners male or female could get concerned if they are being neglected.
What to do? As my current wife and I were chatting about this very topic the other night I think that I could offer some help and support.
Step 1. Get rid of your current partner she sounds a right bunny boiler.
Step 2. Pick the best looking and most healthy female in your walking/climbing group.
Step 3. Having selected your target (new potential partner) hunt her down.
Step 4. Having struck up a physical and very active relationship go at it like rabbits.
Step. 5 While your in this new and exciting relationship maintain contact with all your other female waking/climbing friends,
Step 6. If this new partner has "issues" with you seeing the other females, go back to Step 1.
I hope all this advice helps. I wish someone would helped and given me advice.