I have learned that life is too precious to waste on people you cannot trust. So, no, I would not take a partner back who repeatedly or even once felt the need to be with someone else. I did several times in the past and paid a very heavy price for it. My life has taught me that I can actually be very happy long-term without a partner. It is a different kind of happiness, but it is just as valid.
After choosing to be on my own for 20 years, my Ratter found me and it just felt so right to be with him. I truly love, trust and respect him! But he does know that if I ever felt he were becoming too close to someone else, I would ask him to leave. I believe that if you love your partner, then you will never let anyone else feel they stand a chance of taking liberties with you. If you don't love your partner enough to do that, then don't stay in the relationship! After all, trust that has been broken cannot really be repaired fully. I have found that knowing you are capable of being happy on your own is a wonderful thing. It allows you to be with someone because you truly want to with your whole heart, not because you need to. It gives you the confidence to totally be yourself. This in turn gives your relationship a better chance of success as it is based on honesty, which in turn breeds trust. It is silly little slip-ups that can lead to people outside of a relationship mistakingly thinking they can take liberties. But if two people really love each other, both partners will make every effort to ensure that a wrong impression doesn't endanger a wonderful life together.
End of sermon! LOL :o)