Hi, this is a difficult question to answer as I don't who has prescribed these pills, or what there purpose is.
There is some research into the use of estrogen in anger management in males as it reduces the 'testosterone' element which gives men their driving force and aggression.
I can tell you that the use of these medication when prescribed by a doctor is licensed for the following reasons however that does NOT mean that this is the reason your husband is taking them.
They have been used for treating prostate and breast cancer in men in high doses however your husband's age makes these unlikely.
They have also been used in men who are experiencing trans-gender issues and wish to have a sex change. In very high doses they lead to reduced facial hair, breast growth and atrophy of make genitals. If he had been taking these at high doses then you would have noticed physical changes in the breast area and a reduction in the need to shave so frequently. Smoother facial skin and possibly a change in voice tone would also be noticeable.
I think it may be good for the two of you to sit down and have a chat about these pills. If he does have problem with anger management then your support would help him through this. If there are other issues about trust and secrecy then you may want to take the opportunity to offer him the chance to work as a team, rather than taking the pills behind your back.
Does this help? I will be on and off the computer today but I will keep checking to see if you have any questions.