Based on the fact that there has been some historic jealousy between the two women, while your wife may get 'caught up' in all of the attention, doting behavior etc., toward Jennifer, I suspect that this will actually add
some emotional stress onto your wife, so that she may actually find some peace in respite in her occasional visits with you. What you can do is LISTEN for her stress and simply empathize and support her if she needs to talk or let off a little steam. You can tell if she has a need to do so if she has several new 'stories' to tell about Jennifer, especially if she talks about aspects of her emotionality or personality. Don't particularly comment or offer advice, just be a good listener. IF your wife finds that having Jennifer around is a tad stressful, you will pick up on the cues that reflect this; and you'll immediately realize that your role, if you want to favorably impress your wife, is to support her emotionally. Get her a glass of wine or whatever she wants to drink or eat to relax, offer to take her to a movie for some mindless entertainment if she wants an escape. Offer to get the house emptied out and leave, so she can perhaps take a nap or have quite reading time, etc.
If you talk about yourself, you can mention what you are doing with the anger management class but don't make a big deal about it, as if you were striving to impress her. Just mention it casually and IF your wife asks questions about it, share a bit, but only a bit; if she asks more, tell her a bit more. You don't want to dominate conversations with demonstrations about what you are doing in the area of self-improvement. Being subtle and serene about what you are doing to improve will communicate more loudly that lots of words. If there is hope for the relationship, you must keep reminding yourself that she has to take lots of time to SEE the changes in you and it is only with time that trust can redevelop.
I hope this information is helpful to you. Please let me know if I have overlooked any aspect of your original question. Please click on the green Accept button at the bottom of the screen. Thanks.