Husband and Wife Swimming Together during Niddah

Question: Is there a problem for a husband and wife to swim together in the same pool while she is a niddah? - We are talking about a private pool where there are no mixed swimming issues.
Answer: Yes, it is forbidden for a husband to see his wife not completely dressed when she is a niddah. And even if she is fully dressed and enters the water, it is still a problem since a husband and wife should not frolic when she is a niddah. This does not mean that we should go to the opposite extreme. A husband and wife still have to smile, laugh, etc. during this period of time, but it is not possible to swim together.