I agree with bionicgal, perceptions are everything. Sometimes, one partner's grand gesture falls flat, despite the good intentions behind it. It's definitely a good chance for communication though.
In our case, I discovered my husband's cheating 6 months into our marriage, before we even had rings. He immediately took me ring shopping, to show me that now he was in fact committed. I had a lot of mixed feelings about it (gave it back several times in the 1st few months) but chose to wear it because I saw it meant a lot to him & it represented to me that I had kept our vows.
I personally have come to like the idea of a new ring as a symbol of re-commitment, but understand it is different for everyone.
If nothing else, hopefully this can lead to more communication & better understanding each other's feelings.
It could be manipulative or simplistic on his part or it could be a genuine (but misguided) expression of his good intentions. Hopefully, you can talk it out & come to a compromise you both feel comfortable with.