I start from the assumption that I have no preconceptions. Couples are all different in their own ways. So I observe them in our first contacts. We are all generalizing here. I'm sure i have been with a couple or two over the years where the woman is the prime-mover and the husband/bf is "just going along," but they are very very rare. With my couples, the percentage of males who have raised first bringing me into their sex, versus females who have raised it first is about 60-40%. However, the enthusiasm for continuing our sessions is almost always shared equally, or with the woman taking the lead, somewhat. The second part of your question, if we were compatible outside the bedroom, might a wife leave her hub for me?, takes a longer answer. I don't let it happen. After a few semi and full disasters early in my life, I have learned how to disarm the growth of non-sexual affection in the wife (I have to say, also in the couple. It has happened that both members of the couple have started to fall in love with me). It is hard, because my style is to be as intuitive and open to her sexual emotions as possible. But, although she may be angry at being frustrated in their bedroom, she is married to him, and what she usually wants is to have the burden of the frustration removed. That is my job. That leaves the couple to bond more closely. My style is to encourage their re-bonding... to control my own emotions so that they don't reach beyond our sex... and to short circuit any affection that looks like it may be growing in the wife. Now I've learned how to do all that, while at the same time completely taking over her body while we are fucking... and that can get very emotional, with tears and the rest (and sometimes tears on the hubs part as well). Being the outside man can get very intense... but I like that sort of thing.